stock in trade

WordReference Random House Unabridged Dictionary of American English © 2025

stock′ in trade′, 

1. Business the requisites for carrying on a business, esp. goods kept on hand for sale in a store.
2. resources or abilities peculiar to an individual or group or employed for a specific purpose:
   A feeling for language should be part of the stock in trade of any writer.
Also, stock′-in-trade′. 
• 1660–70

Collins Concise English Dictionary © HarperCollins Publishers::

stock in trade, stock-in-trade noun

1. goods in stock necessary for carrying on a business
2. anything constantly used by a person as a part of his or her profession, occupation, or trade: friendliness is the salesman's stock in trade