[shoal] adj [alter. of ME shold, fr. OE sceald--more at skeleton] (1554): shallow
[2]shoal n (1555) 1: shallow
2: a sandbank or sandbar that makes the water shallow; specif: an elevation which is not rocky and on which there is a depth of water of six fathoms (11 meters) or less [3]shoal vi (1574): to become shallow ~ vt 1: to come to a shallow or less deep part of
2: to cause to become shallow or less deep [4]shoal n [(assumed) ME shole, fr. OE scolu multitude--more at school] (1579): a large group or number: crowd "a ~ of fish" [5]shoal vi (1610): throng, school