Origin: 1565–75; < ML rēctangulum, LL rēctiangulum right-angled triangle (n. use of neut. of rēctiangulus having a right angle), equiv. to rēcti-recti-+ angulumangle1
rec·tan·gle (rěk'tāng'gəl) n. A four-sided plane figure with four right angles.
[French, from Medieval Latin rēctangulum, a right triangle, from Late Latin rēctiangulum : Latin rēctus, right; see reg- in Indo-European roots + Latin angulus, angle.]
1571, from M.Fr. rectangle, from rect-, comb. form of L. rectus "right" + O.Fr. angle (see angle). M.L. rectangulum meant "a triangle having a right angle" (7c.).
In technical analysis, a chart pattern in which the price of a security bounces back and forth between two horizontal lines. Because a rectangle is thought to occur when stock is being distributed or accumulated by knowledgeable investors, a major price movement is expected once the stock breaks out of the rectangle formation.