Wikipedia:

In linguistics, an eggcorn is an idiosyncratic substitution of a word or phrase for a word or words that sound similar or identical in the speaker’s dialect. The new phrase introduces a meaning that is different from the original, but plausible in the same context, such as “old-timers’ disease” for “Alzheimer’s disease”.^[1] This is as opposed to a malapropism, where the substitution creates a nonsensical phrase. Classical malapropisms generally derive their comic effect from the fault of the user, while eggcorns are errors that exhibit creativity or logic.^[2] Eggcorns often involve replacing an unfamiliar, archaic, or obscure word with a more common or modern word (“baited breath” for “bated breath”).^[3]

Melissa Smith, as we were learning the alphabet song:

A, B, C, D, E, F, G!

H, I, J, K, elementary!

[facepalm]

I could spend the whole of this snowy day giggling over the Eggcorn Database, but I need to get out there and take pictures. Maybe of acorns.