To reduce something to a smaller or miniature size; to make something bantam-like (very small or lightweight).
From 'bantam' (a small breed of chicken or anything small) plus the suffix '-ize' (to make or cause to become). It's a modern formation based on the adjective/noun.
Bantamize shows how English constantly creates new verbs—once 'bantam' meant small chickens, then it became an adjective, then we made it a verb to describe any miniaturization process.
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