The noun 'bus' is a noun; a word for a vehicle for transporting passengers, a word for a thing.The word 'bus' is also a verb: bus, buses, busing, bused.The noun form of the verb to 'bus' is the gerund, busing.
Couldn't is called a contraction it is the shortened form of could not. Bus stop is a compound word also: Together Crosswalk Moonlight Football Railroad Sunflower
An abbreviated (or shortened) word for advertisement is 'ad'.
From the Latin omni- meaning 'all, everything', we derive the word omnibus, 'to carry every (one)', which usage has shortened to our current 'bus'.
The word for a shortened form of a word is called a "contraction."
Data bus . Shortened from the Latin word Omnibus (for all)
Fore-clipping words are shortened forms of a word that remove the beginning portion. Examples include phone (from telephone), vet (from veterinarian), and bus (from omnibus).
A contraction is a shortened word. Examples include I'll instead of I will and don't instead of do not. An abbreviation is also a shortened word. Examples include St. for street and Mon. for Monday.
Utility
it is shortened word of "the"
'Ite' in a text message is a shortened word for alright. As in how are you?:)
The word gym is the shortened word of 'gymnasium'