The words kaj, aŭ, sed, plus, minus and nek are conjunctions. For nek read the explanation about negation.

Kaj

Kaj links two things, which have the same role in the sentence:

When mentioning more than two things with the same function we customarily place kaj only before the last one, especially when there is a long list of things. Where there is no kaj you can pause when speaking. In writing you place a comma:

In a colloquial stile kaj is sometimes completely left out:

For emphasis and insistance you can use kaj before each item, also before the first one.

Various relationships between linked sentences

When sentences are linked by kaj, this link can represent various relationships with diverse meanings. To understand what that relationship is, we have to rely on the context:

Aŭ

Aŭ works the same as and. It can link the same things in the same manner, but aŭ shows that the linked items are alternatives. Aŭ shows that one can choose between the linked items, or that it's uncertain which of them is valid.

Usually aŭ is exclusive. This means that only one of the alternatives can be valid. Sometimes, however, aŭ is inclusive. Then it allows us to choose more than one alternative (perhaps even all). Whether aŭ is inclusive or exclusive is shown by the context. To emphatically show that aŭ is exclusive, one can use aŭ before each alternative. To show that aŭ is inclusive we sometimes, especially in writing, use the expression kaj/aŭ: La vojaĝo okazos per trajno kaj/aŭ buso. = La vojaĝo okazos per trajno aŭ buso, aŭ per trajno kaj buso. The trip will be by train or bus or both. We normally don't use kaj/aŭ in the spoken language, only in writing. It might be wise to avoid kaj/aŭ also in writing. It is better to state directly all the available choices.

Sed

The conjunction sed (but) links sentences or clauses, while showing a contrast between them:

Sed often appears together with tamen, which then emphasizes the contrast:

When using tamen one can just as well use kaj instead of sed, because the contrast is quite well expressed by tamen:

Tamen is usually an adject, while sed is a conjunction. For that reason sed comes at the beginning of the sentence while tamen can appear in various positions inside the sentence. Sometimes tamen appears at the beginning of the main clause which is closely tied to the preceding main clause. In that case tamen takes on the role of conjunction. Tamen is practicallly equivalent to sed. One could also say that sed or kaj are inferred: Li estas tre ekkolerema kaj ekscitiĝas ofte ĉe la plej malgranda bagatelo; tamen li estas tre pardonema, li ne portas longe la koleron kaj li tute ne estas venĝema.

Plus and minus

The word plus and minus are mainly used in mathematics and similar expressions to represent the symbols + (plus) and - (minus). Plus shows addition, positivity etc. Minus shows subtraction, negativity etc.

But sometimes plus is used as a conjunction instead of kaj when talking about addition or the like. Similarly minus can replace sed ne when talking about subtraction or the like.

Sometimes plus and minus are used as prepositions similar to kun and sen, so always without a subsequent N-ending. It is however preferable to always use plus and minus as conjunctions according to examples given previously, putting the N-ending when required.

Conjunctions among truncated words

Sometimes, especially in the written language, one uses kaj to link two or more elements of a compound word in order to shorten the sentence:

These types of sentences are quite unnatural. Generally they are not recommended, especially when they include truncated words without grammatical endings, a phenomenon usually impossible in Esperanto. It is preferable to use other methods of abbreviation: