Sometimes it is worth paying close attention to packaging, especially when designing it.

Marina O’Loughlin tweeted a photo of cake packaging from The Cakery, which should put us on alert to begin with. In their description of “Fruit Cake & Lemon Drizzle”, the manufacturer claimed that the fruit cake slice supplied consisted of “fruit cake and a slither of lemon”. Marina was clearly upset, commenting “It’s NOT a bloody ‘slither'”, and Christopher Phin retweeted it, remarking that he hears this often, the use of slither instead of sliver.

(Christopher also raised the question of draw for drawers, but I think that it is safer to keep well away from draw(er)s for the moment.)

The OED gives us two separate nouns, sliver and slither, as well as the more common verb slither.

The meanings given for the noun sliver are:

• a piece cut or split off, such as a splinter or slice, and figurative uses, which it traces back to Chaucer in 1374,
• the same applied to parts of trees or plants,
• the side of a small fish sliced off for use as fishing bait, which it reports as an American usage,
• a continuous ribbon or band of loose and untwisted fibres of wool or other textile material, ready for processing into yarn,
• three minor technical uses in the nineteenth century,
• a slashing cut or stroke,
• as sliver-edge, a very fine edge on a piece of timber.

(There is another noun sliver given, which is of doubtful meaning and need not concern us here.)

The meanings which the OED gives for the noun slither are:

• loose stones lying in large amounts on the side of a hill, which it considers to be primarily Scots English (also as sclither),
• a local meaning similar to that,
• a technical meaning, as the filling placed between the inner and outer soles of shoes,
• a slipping or sliding, which can be transferred and figurative, and dates back to the middle of the nineteenth century,
• something smooth and slippery; a smoothly sliding mass; the same as the first meaning of ‘sliver’, i.e. a piece cut or split off.

The cake packaging was obviously using slither in the sense of a slice, a piece cut off a lemon. Under those definitions, this could be either sliver in its first meaning, or the last option of the last meaning of slither, in which it has the same meaning as sliver.

It is worth looking at the quotations which the OED kindly supplies to illustrate this.

The first is from Ezra Pound, Quia Pauper Amavi (1919). On page 40, he starts:
If she with ivory fingers drive a tune through the lyre,
We look at the process
How easy the moving fingers; if hair is mussed on her forehead,
If she goes in a gleam of Cos, in a slither of dyed stuff,
There is a volume in the matter; if her eyelids sink into sleep,
There are new jobs for the author,
And if she plays with me with her shirt off,
We shall construct many Iliads.

The only dictionary meaning of slither which makes any sense there is the last, which could perhaps be either of the first senses, but is more plausibly that which is the same as the first meaning of sliver, or possibly even its fourth meaning, the band of loose and untwisted fibres. It thus looks possible that Pound used slither for sliver.

There are then two quotations which apply slithers to water:
Only after rain, when the rocks are hung with slithers of water like lace curtains against the black slate. (1955)
Little fenced saucers of earth where a few palm-trees grew and slithers of water gleamed between. (Graham Greene’s Comedians, 1966.)
Again only the last meaning of slither is plausible, and they may have been using it instead of sliver.

The final quotation is from that bastion of the British Conservative middle class, the Daily Telegraph, on 27 May 1981:
Calvin Klein’s newest dress is a slither of silk shaped simply like an overgrown T-shirt.
Whilst silk fabric is certainly smooth and slippery, this again could have been a sliver meaning.

As a noun, slither is a very uncommon word in English, whereas sliver is considerably more common even than the verb slither. So the Google Ngram frequencies for slither of and sliver of (in which the word in question almost has to be a noun) are particularly revealing.

In either British or US English books, sliver of and slither of only start to appear with any frequency after 1900, although sliver (with or without of) appeared throughout the nineteenth century too. Sliver of remains more common than slither of, by a factor of around ten. However it looks as if slither meaning a slice or piece cut off, instead of sliver, has been appearing since about 1900.

So according to the OED “a slither of lemon” is not incorrect, and according to usage since 1900, it is less common than “a sliver of lemon”, but is in use in both British and American English.

I think I still prefer to separate the meanings of the two words, but it would be peevish to insist that others do too.