A. Coördinate use.
Connective: A word connecting a word, phrase, clause, or sentence with that which precedes it: a colorless particle without an exact synonym in English, but expressed approximately by ‘with, along with, together with, besides, also, moreover,’ the elements connected being grammatically coördinate.
When many words, phrases, clauses, or sentences are connected, the connective is now generally omitted before all except the last, unless retained for rhetorical effect. The connected elements are sometimes identical, expressing continuous repetition, either definitely, as, to walk two and two; or indefinitely, as, for ever and ever, to wait years and years.
The repetition often implies a difference of quality under the same name; as, there are deacons and deacons (that is, according to the proverb, “There's odds in deacons”); there are novels and novels (that is, all sorts of novels). To make the connection distinctly inclusive, the term both precedes the first member: as, both in England and in France. For this, by a Latinism, and … and has been sometimes used in poetry (Latin and French et … el).
Introductive: in continuation of a previous sentence expressed, implied, or understood.
In this use, especially in continuation of the statement implied by assent to a previous question. The continuation may mark surprise, incredulity, indignation, etc.: as, And shall I see him again? And you dare thus address me?
Adverbial: Also; even.
Hence, but and, and also: common in the old ballads.
B. Conditional use.
If; supposing that: as, and you please
Disadvantage ys, that now childern of gramer-scole conneth no more Frensch than can here lift [their left] heele, & that is harm for ham [them] & a [if they] scholle passe the se, & trauayle in strange londes.
Often with added if (whence mod. dial. an if, nif, if). Hence, but and if, but if.
A prefix in Middle English and Anglo-Saxon, represented in modern English by an- in answer, a- in along, and (mixed with original on-) by on- in onset, etc.