The Collaborative International Dictionary of English v.0.48:

Loch \Loch\ (l[o^]k), n. [Gael. & Olr. loch. See Lake of
   water.]
   A lake; a bay or arm of the sea. [Scot.]
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Loch \Loch\ (l[o^]k), n. [F. looch, Ar. la'[=u]g, an electuary,
   or any medicine which may be licked or sucked, fr. la'[=u]q
   to lick.] (Med.)
   A kind of medicine to be taken by licking with the tongue; a
   lambative; a lincture.
   [1913 Webster] Lochaber ax

WordNet (r) 3.0 (2006):

loch
    n 1: a long narrow inlet of the sea in Scotland (especially when
         it is nearly landlocked)
    2: Scottish word for a lake

Moby Thesaurus II by Grady Ward, 1.0:

73 Moby Thesaurus words for "loch":
   arm, armlet, artificial lake, bay, bayou, bayou lake, belt, bight,
   boca, cistern, cove, creek, dam, dead water, dike, estuary, etang,
   euripus, farm pond, fishpond, fjord, freshwater lake, frith,
   glacial lake, gulf, gut, harbor, inland sea, inlet, kyle, lagoon,
   laguna, lake, lakelet, landlocked water, linn, lough, mere,
   millpond, millpool, mouth, narrow, narrow seas, narrows,
   natural harbor, nyanza, oxbow lake, plash, pond, pondlet, pool,
   puddle, reach, reservoir, road, roads, roadstead, salina,
   salt pond, sound, stagnant water, standing water, still water,
   strait, straits, sump, tank, tarn, tidal pond, volcanic lake,
   water hole, water pocket, well