Merriam-Webster's Collegiate® Dictionary, 11th Edition
TIDE
I. noun
Etymology: Middle English, time, from Old English tīd; akin to Old High German zīt time and perhaps to Greek daiesthai to divide Date: before 12th century
1. a space of time ; period , a fit or opportune time ; opportunity , an ecclesiastical anniversary or festival,
2. a. the alternate rising and falling of the surface of the ocean and of water bodies (as gulfs and bays) connected with the ocean that occurs usually twice a day and is the result of differing gravitational forces exerted at different parts of the earth by another body (as the moon or sun), a less marked rising and falling of an inland body of water, a periodic movement in the earth's crust caused by the same forces that produce ocean tides, a periodic distortion on one celestial body caused by the gravitational attraction of another, one of the periodic movements of the atmosphere resembling those of the ocean and produced by gravitation or diurnal temperature changes, flood tide 1,
3. something that fluctuates like the tides of the sea , a surging movement of a group ,
4. a flowing stream ; current , the waters of the ocean, the overflow of a flooding stream, tideless adjective
II. verb (tided; tiding)
Date: 1593
intransitive verb to flow as or in a tide ; surge , transitive verb to cause to float with or as if with the tide,
III. intransitive verb (tided; tiding)
Etymology: Middle English, from Old English tīdan; akin to Middle Dutch tiden to go, come, Old English tīd time Date: before 12th century betide , befall