A tool used with a mortar (乳鉢) for grinding or mixing substances, commonly in pharmacy, chemistry, or cooking.
薬剤師は乳棒と乳鉢で薬をすりつぶした。
The pharmacist ground the medicine with a pestle and mortar.
churn dasher; milk agitator
Formed in association with 乳鉢 “mortar”: 乳棒 is the 棒 used to grind substances in that vessel.