Ad lib is an abbreviation of the phrase ad libitum, which is Latin meaning "at one's pleasure." When you ad lib you are improvising or making something up without any preparation.
An ATM is an Automatic Teller Machine. You put your keycard or credit card into it to deposit or withdraw money.
Bike is short for bicycle. More people use the short form bike than the long form bicycle.
Bayerische Motoren Werke AG, shortened to BMW, is a German car maker that also make motorbikes and engines.