a tad

昨日取り上げたFat Cellの記事の続きの個所にも覚えたい単語がありました。
Back in his university days, when The Body played sport or cycled almost every weekend, his weight was under control.
His diet had a lot less sugar, and his brain listened to my leptin warnings, quashing his hunger whenever I managed to plump up.
Sure, I'd get a little ahead after a big weekend of beer and wings, inflate a tad.
"tad" とは何でしょうか？　連想するのは "tadpole" 位ですが、ここでは関係がないのは明白です。辞書で "tad" を調べます。
・Collins Dictionary: (US & Canadian) a small bit or piece: "Well, I cheated a little," Fiona confessed, lowering her voice a tad.
・Macmillan Dictionary: a little bit: Add just a tad more sugar.
ついでに語源辞典を見ると、何と "tadpole" と関係があったのには意外でした。
Online Etymology Dictionary: 1877, "young or small child," probably a shortened form of tadpole, which is said to be the source of Tad as the nickname of U.S. President Lincoln's son Thomas (1853?1871). The extended meaning "small amount" is first recorded 1915.