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To add something on to something else. A noun or pronoun can be used between "tack" or "on." Miss, can I tack a side of bacon onto my order? If you kids keep talking, I'll tack another essay onto your homework.
1. To attach something to a surface using a tack, pin, or nail: I tack my children's drawings on the kitchen door. The teacher set up a big corkboard, and each child tacked on a poem.
2. To add or append something additional: The hotel tacked on a five percent service fee. I read my essay again and tacked an introduction on.