Wiktionary
a. (context archaic English) athwart; from side to side; across. adv. (context archaic English) Athwart; from side to side; across.
WordNet
adj. extending or lying across; in a crosswise direction; at right angles to the long axis; "cross members should be all steel"; "from the transverse hall the stairway ascends gracefully"; "transversal vibrations"; "transverse colon" [syn: cross(a), transverse, transversal]
Usage examples of "thwartwise".
Amidships stood half a dozen horses separated one from the other by slender poles affixed thwartwise from wale to wale, and at the prow stood Vanidar, Aravan right behind, the warleader and his trusted advisor sailing away from the caer.
The shipyards, however, were a hive of activity, the wrights working throughout the nights as well as the days: fifty of the Dragonships were measured and fitted thwartwise with wide, raftlike sections of heavy planks pinned to the underbracing, to span across from topwale to topwale and jut a yard beyond either side.
The three hunched forward over their table, hats pulled thwartwise across their yellow faces.