Is it (GeerRoo) or (GuyRoo) or What?
How do you pronounce gyro?
A fair number of our users are unsure of how to pronounce gyro. This isn't surprising, since there are two different gyros and they have two different pronunciations.
The earlier gyro is the one that is a shortened form of gyrocompass or gyroscope, and it has a pronunciation that conforms to one's expectations: /JEYE-roh/. But few people encounter this gyro in the course of everyday life; they generally run into the other gyro, a sandwich of lamb or beef usually served on pita and with a yogurt sauce. That gyro has two main pronunciations: /YEE-roh/ and /ZHIHR-oh/.
The sandwich gyro was borrowed into English from Modern Greek in the 1970s and English speakers have given it an approximation of the Greek pronunciation. The earlier gyro has been fully phonetically anglicized.
This comes from Merriam-Webster definition.