mainspring mainsheet • mainstay · · · Info · Definitions · Characters · · mainspring · · Text Latin · · Script 10 · · Length Definitions · · · (noun) the most important spring in a mechanical device (especially a clock or watch); as it uncoils it drives the mechanism. · · Noun Definition 1 Characters · · a latin small letter a U+0061 g latin small letter g U+0067 i latin small letter i U+0069 m latin small letter m U+006D n latin small letter n U+006E p latin small letter p U+0070 r latin small letter r U+0072 s latin small letter s U+0073