noun [ U ]
1.
/ ˌpiː iː ˈtiː; NAmE / an artificial substance used to make materials for packaging food, including plastic drinks bottles (the abbreviation for 'polyethylene terephthalate')
2.
/pet/ ( medical ) a process that produces an image of your brain or of another part inside your body (the abbreviation for 'positron emission tomography') :
a PET scan
3.
/pet/ a British test, set by the University of Cambridge, that measures a person's ability to speak and write English as a foreign language at an intermediate level (the abbreviation for 'Preliminary English Test')