This word stays right at the front of your mouth, as though you were worrying a flaxseed with your incisors. It can be said quickly with the merest movement of the mouth and just a smidgen of sound. It has clear echoes of midge and midget, both words for diminutive objects, but it’s not too far from fridge and bridge either. The /sm/ onset brings flavours from many words: small, smack, smash, smattering, smear, smell, smile, smirch, smirk, smite, smithereen, smooch, s’more, smother, smudge, smush… And the high front vowel sets the size at small; you know it’s somewhat less – and neater – than a splodge.
It showed up in English in the mid-19th century, but we’re not sure where from. Perhaps from smitch. “Oh, right, smitch!” you say. “Uh…” Yes, smitch is a no-longer-used word meaning “a little bit.” And it? “Of doubtful origin,” the Oxford English Dictionary declares. Oh, come on lads, give us some etymology. Just a smidgen?
To look at, certainly, this word is not unusually small; in sight and sound it has two parts, easily snapped in half for those who want less. But write that half down and it’s almost as big as it was to start with – smidge – which is unsurprising: how often have you said you wanted only a bit and then had nearly the whole thing?