Under the Whyte notation system, a steam locomotive that has two leading wheels followed by two sets of coupled driving wheels, and no trailing wheels.

Under the Whyte notation system, a steam locomotive that has two leading wheels arranged in a leading truck, four coupled driving wheels and four trailing wheels in a trailing truck.

Under the Whyte notation system, a steam locomotive that has two leading wheels arranged in a leading truck, eight coupled driving wheels and four trailing wheels in a trailing truck.

Under the Whyte notation system, a steam locomotive that has four leading wheels arranged in a leading truck, eight coupled driving wheels and two trailing wheels in a trailing truck.

Under the Whyte notation system, a steam locomotive that has two leading wheels, six coupled driving wheels, and six trailing wheels.

Under the Whyte notation system, a steam locomotive that has four coupled leading wheels, ten coupled driving wheels, and one pair of trailing wheels.

(rail transport) Under the Whyte notation system, a steam locomotive that has four coupled leading wheels, six coupled driving wheels, and a pair of trailing wheels. Also known in UK English as a "Pacific" locomotive.

Under the Whyte notation system, a steam locomotive that has four coupled leading wheels, twelve coupled driving wheels, and one pair of trailing wheels.

(US) A pencil which produces a specific shade of dark gray. One can usually identify a number 2 pencil by looking for the number "2" conspicuously emblazoned on the pencil. Often required for test-taking and the completion of official forms.

Under the Whyte notation system, a steam locomotive that has two leading wheels, six pairs of coupled driving wheels, and four trailing wheels.