Plain meaning
Start with the shortest useful explanation before going deeper.
A Bitcoin soft fork activated in November 2021 (BIPs 340-342) introducing Schnorr signatures for efficient key/signature aggregation, MAST (Merkelized Abstract Syntax Trees) for committing complex spending conditions where only the exercised branch is revealed on-chain, and Tapscript extending Bitcoin Script with new opcodes. Taproot makes complex transactions (multisig, timelocks, conditional spending) indistinguishable from simple single-key transactions, improving privacy and efficiency.