Why the shortening of “fitted” to “fit”?

Question

Which is more correct, "it fit really well" or "it fitted really well"? The short form is something I encountered when moving to the US, I never heard it in the UK.

Answer 1

The definition of 'fit' used here is given by the OED (5.a.) as:

To be of the right measure or proper shape and size for; to be correctly shaped or adjusted to. Said esp. of dress; also fig.

One of the two earliest quotes for this definition in the past tense uses 'fit'; the other uses 'fitted'.

a1691 BOYLE Firmness Wks. 1744 I. 278 As much of the stone, as was contiguous to the marchasite..fitted the marchasite so close as if [etc.].

1795 BURNS Song, Last May, a braw wooer, And how her new shoon fit her auld schachl't feet.

So both forms have been in use for a long time.

Searching COCA, COHA, and the BNC for "fit well" vs. "fitted well," I found "fit well" outnumbering "fitted well" by 20:1 in COCA (indicating American usage), 8:3 in the COHA (indicating older American usage), and by 2:1 in the BNC (for you Brits). So either is fine, on both sides of the Atlantic, but "fit well" is much more common in modern American usage.

Answer 2

I think there are two separate verbs here that are the same in the present tense but different in the past.

1. To fit the way clothing fits. "This outfit fits me fine. Did that outfit fit you? Yes it fit me."
2. To fit as in to equip. "We fit our men with the best rifles. I was fitted with the best equipment."