What does "grip" mean when describing a wine?

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Dear Dr. Vinny,
I often come across the word “grip” in describing wine. What does it mean?
—H.F. Chew, Malaysia
Dear H.F.,
It depends on the context, but “grip” is usually a positive note, referring to the pull on the sides of your mouth you get, particularly when drinking a red wine. It’s a way to describe a wine’s structure, and when I hear “grip,” I usually assume one is talking about tannins, though sometimes a white wine with high acidity can give a gripping sensation.
Grip is good, a welcome firmness. It gives definition and texture to wine, similar to descriptions like traction or backbone. It helps wines avoid seeming flabby, though with too much grip a wine might veer towards drying.
—Dr. Vinny