noun
abacus bead
Refers to the individual beads on a Japanese abacus (soroban).
そろばん玉をはじいて計算する。
Calculate by moving the abacus beads.
そろばん is the abacus itself, while そろばん玉 refers specifically to its beads.
Compound of そろばん (abacus) and 玉 (ball, bead).