But: if this is a from a larger set, and the answer length is given as 3 letters, then "by 3" means the word is 3 letters long, and the preceding text gives the wordplay.
But simpler: the answer is likely (three in prefix form) — but "twbydy"?? Maybe "tw" = two, "bydy"??
But the simplest interpretation: = two-by-two = 4; "am" = AM; "by 3" = next to 3 → "4AM beside 3" → puzzle answer "TRI" (three) as the piece.
If the answer is just ? "twbydy" = two by two = square, "am" = morning = A.M., "by 3" = ×3? Not fitting.
However, if the dash before "piece" means the answer is hyphenated, "three-piece" fits, but the clue gives 3 letters. Could it be ?
But without more context, the cleanest match to a 3-letter "piece" is (as in a piece of something) — but the wordplay "twbydy" doesn't yield that.
