Cellular phone and Keitai

Cellular phone noun - A hand-held mobile radiotelephone for use in an area divided into small sections, each with its own short-range transmitter/receiver.

Keitai and cellular phone are semantically related. In some cases you can use "Keitai" instead a noun phrase "Cellular phone".

Cellular phone and keitai are semantically related. You can use "Cellular phone" instead a noun "Keitai".