(past should; present singular & plural shall)
Etymology: Middle English shal (1st & 3d singular present indicative), from Old English sceal; akin to Old High German scal (1st & 3d singular present indicative) ought to, must, Lithuanian skola debt
Date: before 12th century
a. will have to ; must
b. will be able to ; can
a. — used to express a command or exhortation <you shall go> b. — used in laws, regulations, or directives to express what is mandatory <it shall be unlawful to carry firearms> 3. a. — used to express what is inevitable or seems likely to happen in the future <we shall have to be ready> <we shall see> b. — used to express simple futurity <when shall we expect you> 4. — used to express determination <they shall not pass> intransitive verb archaic will go <he to England shall along with you — Shakespeare> Usage: From the reams of pronouncements written about the distinction between shall and will—dating back as far as the 17th century—it is clear that the rules laid down have never very accurately reflected actual usage. The nationalistic statements of 18th and 19th century British grammarians, who commonly cited the misuses of the Irish, the Scots, and occasionally the Americans, suggest that the traditional rules may have come closest to the usage of southern England. Some modern commentators believe that English usage is still the closest to the traditionally prescribed norms. Most modern commentators allow that will is more common in nearly all uses. The entries for shall and will in this dictionary show current usage.
New Collegiate Dictionary. 2001.