Once when the Buddha was living in the gabled hall in the large grove outside Vaiśālī his maternal aunt and foster mother Mahāpajāpatī Gotamī came to visit him.  She was about to set off on a solitary retreat and asked the Buddha for something pithy to reflect on. The Buddha gave her eight pairs of antonyms which he told her define what the Dhamma is and is not. These were:
- sarāga/virāga - passion/dispassion
- saṃyoga/visaṃyoga - attachment/detachment
- ācaya/apacaya - accumulation/divestment
- mahicchatā/appicchatā - ambition/satisfaction
- asantuṭṭhi/santuṭṭhi - discontentment/contentment
- saṇgaṇika/paviveka - society/solitude
- kosajja/vīriyārambha - idleness/invigoration
- dubbharatā/subbharatā - burdensomeness/helpfulness
While I do understand the nature of irony, allow me to give a slightly earnest answer to NellaLou. I think this kind of text shows that as well as trying to pin things down, there is a trend in Buddhism which holds the doctrines and practices loosely. Here we have the Buddha saying basically "anything that works is the Dharma". I would qualify 'works' here with the caveat that it has to definitely lead to the positive side of the equations given.
We could also see the fundamentalist cant in the light of the obvious borrowings throughout the history of Buddhism - from Vedism, from Jainism, from Hinduism, from Śaivism, from Taoism, from Shamanism, etc. We have historically been able to reform, innovate and incorporate because conservatives and fundamentalists have not always held sway. However I think it's easy to overstate the influence of online fundamentalists - I find the real Buddhists and Buddhologists I meet tend to be friendly and open. It's probably worth pointing out that our central doctrine in Buddhism is that EVERYTHING CHANGES! I think conservatives and fundamentalists lose sight of this, and perhaps even fear change.
Now although there are eight terms a number of them are synonyms - it can be quite difficult to see whether an entirely different concept is intended, or if a synonym is being used for reinforcement (a very common Pāli rhetorical strategy). Although I've gone for a single word in each case, it should not be assumed that the English precisely conveys the Pāli - far from it. Take the word rāga in sarāga/virāga 'with/without passion'. What's intended here is something like 'uncontrollable excitement'. It is not passion in the contemporary sense of 'positive enthusiasm' for something, but in the archaic sense of a strong emotion or event which overtakes us against our will - the Passion of Christ refers to his torture and horrible death on the cross for instance; and the passion of various saints refers to their martyrdom. So rāga is passion in this negative sense.
The pairs saṃyoga/visaṃyoga and saṇgaṇikā/paviveka are related: they value independence and individuality over dependence and groups. Following Sangharakshita we tend to use this word 'group' pejoratively in the Triratna Buddhist Order - it represents the lower evolution, the herd, the mob, the submerging of the individual will rather than it's sublimation. "The group is always wrong"... "the couple is a group of two" etc. The Buddha certainly valued individuality and emancipation from the herd mentality. He often encouraged his followers to leave behind family, status, career and social groups and to pursue enlightenment alone in the wilderness. There is only misery in those kinds of attachments (cf From the beloved). We can of course take this too far because the spiritual community can come together on a different basis, which I discussed in my post on the Russian term sobornost.
Similarly there are some pairs dealing with our hedonic response to sense data: mahicchatā/appicchatā; asantuṭṭhi/santuṭṭhi. The first two revolve around the word iccha 'wish, desire' as an abstract noun icchatā 'wishfulness'. The negative side has much (mahā) of this, while the positive has little (appa). Similarly the second pair revolve around the word tuṭṭha 'pleased, content'. The negative is dissatisfaction, the positive is satisfaction - both appicchatā and santuṭṭhi could be rendered as 'contentment'.
Lastly we have kosajja/vīriyārambha and dubbharatā/subbharatā. These relate to how we contribute to society. The pair of idleness (kosajja) or invigoration (vīriya-ārambha) is fairly obvious. The last pair are more difficult. The base is bharatā from the root √bhṛ 'to bear' (and related to English words ending in -fer/-pher e.g. aquifer 'water bearer'; Lucifer 'light bearer'). The word is an abstract noun that only seems to occur in these two compounds. In this context it refers to being easy (su) or difficult (du) to support, probably with reference to bhikkhus who may require little or much from their supporters. In The Life of the Buddha Ñāṇamoli renders the pair as 'luxury' and 'frugality',  while Thanissaro opts for 'burdensome/unburdensome'.  I've gone for helpful as the opposite of burdensome because it coveys an active rather than a passive value: why stop at just not being a burden and when one can do something helpful? One who is idle is a burden so these terms are to some extent synonymous.
A small point of interest about satthusāsana which I have rendered as 'the instruction of the instructor'. Both parts of the compound (satthu and sāsana) derive from √śās which has a range of senses from 'chastise, punish'; through 'control, rule, order, command'; to the more benign 'instruct, teach'. From it we also get the word śāstra 'a text for instruction' (as distinct from śruti 'what is heard, a sacred text'). So we could have rendered it 'the command of the commander', or the 'teaching of the teacher'. In the case of Aśoka's edicts (i.e. sāsanā) we might go for 'the dictates of the dictator'.
This is a strange text in some ways. It is unusual that there is no response to the teaching from Mahāpajāpatī. We would expect her to have something to say, and it would not be unusual for her to disappear for a week or two and come back and report that she had 'done what had to be done' (i.e. become an arahant), though she does later become an arahant. Indeed this is a strange meditation practice and it feels like we're missing some important piece of the story. Mahāpajāpatī asks for something concise that she might dwell on alone, secluded, vigilant, ardent and resolute (ekā vūpakaṭṭhā appamattā ātāpinī pahitattā vihareyyaṃ). And the Buddha responds in a very abstract way. It's hard to see this would be helpful unless she had a problem of being too narrow in defining the Dharma, or was struggling to interpret conflicting interpretations (and as NellaLou has pointed out these issues are endemic in Buddhism). According to the Dictionary of Pāli Names this story occurs after her ordination (and the creation of the bhikkhunī saṅgha) when she is already a stream-entrant (sotāpanna).
What ever we make of the context, the attitude displayed in the sutta is a useful antidote to narrowness, conservatism and fundamentalism. 'Buddhism' is anything that genuinely leads to positive results as defined by the Buddha, i.e. anything that leads to: dispassion, detachment, divestment, satisfaction, contentment, solitude, invigoration, helpfulness. Of course we don't really need a text to tell us this, or to justify our practice to others if we feel we are genuinely practising, but I find it useful to show that even the conservative Theravādins preserved a tradition of openness and innovation.