1.
vinegar
Vinegar used in cooking. The polite prefix お makes this the standard everyday form; plain 酢 sounds blunt in conversation.
The polite prefix お is almost always used in everyday speech; plain 酢 appears mainly in compound words and technical contexts. Common collocations: お酢をかける (to put vinegar on), 酢の物 (vinegared dish), 酢飯 (vinegared sushi rice). Types of vinegar: 米酢 (rice vinegar), 穀物酢 (grain vinegar), 黒酢 (black vinegar). Related: 酸っぱい (sour — shares the same kanji root).