and

and/or

is a formula indicating that the items connected by it can be taken either together or as alternatives. Its principal uses are in legal and other formal documents (These ratios indicated that the changes in the order of crystallinity were similar to those with the water content and/or dehydration and temperature for gelatinization among and/

• or within cultivars —Annals of Botany, BrE 2001)

and in logic (The best philosophy…embodies a picture of the world and/

• or a set of values —E. Craig, 2002).

In general use the effect can be ungainly:

• Stalin, characteristically insensitive to Western public opinion and/or relying on the political ambiguity of these phrases in the existing context, signed it —Cambridge Review, 1959.

A more comfortable way of expressing the same idea is to use ‘X or Y or both’, and in some cases ‘or’ by itself will do.

————————

and

1. The simplest-looking words are often among the most complicated in use, and and is no exception. The normal function of and is to join words, phrases, and sentences: John and Mary are brother and sister / They dealt with the matter quickly and efficiently / an acute and wary sense of the ordinary. In some cases it links parallel words that form a fixed expression that cannot normally be reversed (fish and chips, ☒ chips and fish; first and foremost, ☒ foremost and first; Romeo and Juliet, ☒ Juliet and Romeo).

2. For guidance on grammatical agreement in sentences with subjects containing and (e.g. Fish and chips is/are my favourite meal), see agreement.

3. And is often omitted for contextual effects of various kinds, especially between sequences of descriptive adjectives which can be separated by commas or simply by spaces

• (The teeming jerry-built dun-coloured traffic-ridden deafening city —Penelope Lively, 1987).

4. There is a persistent belief that it is wrong to begin a sentence with And, but the practice will be found in literature from Anglo-Saxon times onwards, especially as an aid to continuity in narrative and dialogue. The OED provides examples from the 9c to the 19c, including one from Shakespeare's King John: Arthur. Must you with hot Irons, burne out both mine eyes? Hubert. Young boy, I must. Arthur. And will you? Hubert. And I will. It is also used for other rhetorical purposes, especially to denote surprise

• (O John! and you have seen him! And are you really going? —1884 in OED)

and sometimes just to introduce an improvised afterthought

• (I'm going to swim. And don't you dare watch —G. Butler, 1983).

It is however poor style to separate short statements into separate sentences when no special effect is needed: I opened the door and I looked into the room / ☒ I opened the door. And I looked into the room.

5. And all is a well-established tag added to the end of a statement, as in

• Isn't it amazing? He has a Ph.D. and all —J. Shute, 1992.

With the nominal meaning ‘also, besides, in addition’, the use has origins in dialect, as can be seen from the material from many regions given in the English Dialect Dictionary (often written in special ways, e.g. ano', an'-all, an' a'). In many of the examples it seems to lack any perceptible lexical meaning and to be just a rhythmical device to eke out a sentence.

6. And also has special uses, to show progression (faster and faster), cause and effect (do that and I'll send you to bed), duration (they ran and ran), a large number or quantity (miles and miles), and addition (four and four are eight), purpose (where and replaces to: Try and come tomorrow). See also try and.

7. Another special use, recorded in the OED from the 16c, is to express ‘a difference of quality between things of the same name or class’, as in W. S. Gilbert's lines from The Gondoliers (1889): Well, as to that, of course there are kings and kings. When I say I detest kings I mean I detest bad kings. To this we may add some modern examples:

• There are ways to steal and there are ways to steal —New Yorker, 1988

• There is homelessness and homelessness.…The sort of homelessness which means despair is quite different from the sort that means adventure —Times, 1991.