Did you consider yourself a mathematician the last time you sat down to solve a Sudoku puzzle? It’s certainly a mentally ...

Explore news and insights on climate change, environment policies, global warming and sustainable practices with The New York Times Climate and Environment section.

A trademark is a recognizable sign, phrase, or symbol that denotes the ownership of a particular product or service and legally differentiates it from all others of its kind.

A brokerage firm acts as an intermediary who makes matches between buyers and sellers of stocks, bonds, and other financial assets.