noun
one's own thing; thing held in one's hand
Literally refers to something one holds or possesses; can also imply something one is accustomed to handling.
彼はいつも手のものを離さない。
He never lets go of the thing in his hand.
noun
one's specialty; one's forte; one's strong point
Idiomatic use, often in the phrase お手のもの, meaning something one is particularly good at or skilled in.
See also: お手の物
料理は彼女のお手のものだ。
Cooking is her forte.
Polite prefixed form commonly used in the idiomatic sense of 'one's specialty'.
Compound of 手 (hand) + の (possessive particle) + もの (thing). The idiomatic sense likely developed from the idea of something always at hand or well-practiced.