Partly. Britannica defines the piano as a keyboard instrument whose wire strings sound when they are struck by felt-covered hammers operated from the keys. Because the sound starts with a hammer strike, the piano is sometimes grouped with percussion, and orchestras often seat it with the percussion section.
The tone itself, however, comes from vibrating strings, which pass their vibration through a bridge to a soundboard that amplifies it. For that reason, instrument classifications usually treat the piano as a struck-string keyboard instrument rather than a true percussion instrument such as a drum.
Source: Encyclopaedia Britannica, “Piano”
Image: Grand piano action, piano hammers, at Steinway Pianos of Calgary, by Rhona-Mae Arca, CC BY 2.0, via Wikimedia Commons.