noun
Etymology: from Tom, nickname for Thomas
1. usually capitalized L&T
a. : a long pivot gun formerly carried on the deck of a warship
the Long Tom roared from his pivot and the grapeshot fell like hail — J.J.Roche
b. : a large gun having a long range used on land ; especially : a United States 155 millimeter rifled gun used during World War II
2.
a. England : long-tailed tit
b. : any of several Australian needlefishes
3. : a trough for washing gold-bearing earth