Real Dictionary

START in American English
Strategic Arms Reduction Talks
to make a sudden, involuntary or unexpected movement, as when surprised; jump, leap, jerk, etc. in a startled way
intransitive verb: to begin or set out, as on a journey or activity
noun: a beginning of an action, journey, etc
noun: Strategic Arms Reduction Treaty
transitive verb: to set moving, going, or acting; to set in operation

start in British English
noun acronym for: Strategic Arms Reduction Treaty: a series of agreements between the US and the USSR (and then Russia) to reduce nuclear weapons
verb: to begin or cause to begin (something or to do something); come or cause to come into being, operation, etc