noun
Usage: usually capitalized J
Etymology: after Jacob St. James, symbolized in religious art by a pilgrim's staff — more at jacobin
1. obsolete : a pilgrim's staff
2.
a. obsolete : cross-staff 2
b. also jacob staff : a short square rod with a cursor used for measuring heights and distances
c. also jacob staff : a straight rod or staff pointed and shod with iron at the bottom for insertion in the ground, having a socket joint at the top, and used instead of a tripod for supporting a compass
3. obsolete : a staff with a sword or dagger concealed in it