Is it ensure, insure, or assure?
"dealer in poultry," 1630s, a redundancy, but it has largely ousted original poulter (mid-13c., pulter), from Anglo-French poleter, pulleter, Old French pouletier "poulterer," from pouletrie (see poultry). With agent suffix -er (1). Poetic poulter's measure (1570s), according to Miller Williams, is "So called because with its thirteen feet it suggests the poulter's old practice of giving an extra egg with the second dozen." ["Patterns of Poetry," Louisiana State University, 1986].