noun
Refers to something that sticks out physically, such as a ledge, a part of a building, or a protruding object.
この机の突き出し部分に気をつけてください。
Please be careful of the protruding part of this desk.
Commonly served at izakaya or bars, often a small dish that comes before the main order; sometimes automatically added to the bill as a cover charge.
居酒屋で最初に出てくる突き出しは、お通しとも呼ばれます。
The appetizer served first at an izakaya is also called 'otoshi'.
noun
frontal thrust out (sumo technique)
A sumo winning technique where the wrestler pushes the opponent out of the ring with a frontal thrust.
横綱は強烈な突き出しで相手を土俵の外に押し出した。
The yokozuna pushed his opponent out of the ring with a powerful frontal thrust.
Compound of 突き (tsuki, 'thrusting') + 出し (dashi, 'putting out'). The appetizer sense likely derives from the idea of something 'thrust out' or 'presented' to the customer.