(since it says "piece" in the prompt): "TRI" or "TRIO" ? But length 3 → "TRI" .
But in cryptic crosswords: "piece" often means a part or a chess piece. "by 3" = tri- prefix. Could "twbydy" be "two b y d y" → musical notes? B, D?
Given typical puzzle answer lengths, is a clue for "AM" with something? No.
But simpler: the answer is likely (three in prefix form) — but "twbydy"?? Maybe "tw" = two, "bydy"?? twbydy-am-by-3
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.
Given the ambiguous nature, I think this is a cryptic instruction: is an anagram of "two by dy" = two by dy? dy = dysprosium. No.
(Roman numeral for 3, "piece" as in a piece of a set). (since it says "piece" in the prompt): "TRI" or "TRIO"
Alternatively: the answer might be (Roman 3) as the "piece".
Given typical cryptic answers: I’ll go with (from tri = three, "by 3" = times three, "am" = "I am" = "I" in Latin? No).
However, if the dash before "piece" means the answer is hyphenated, "three-piece" fits, but the clue gives 3 letters. Could it be ? "by 3" = tri- prefix
Given the obscure nature, I’ll answer:
Given the cryptic style, I suspect ; "am" = morning = "AM"; "by" = next to; "3" = three letters; total maybe "FOUR AM" → anagram?
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 the simplest interpretation: = two-by-two = 4; "am" = AM; "by 3" = next to 3 → "4AM beside 3" → puzzle answer "TRI" (three) as the piece.
The string appears to be a cryptic clue in the style of a cryptic crossword.