(physics) wavelength

radio / (slang, dated) broke, having no money; dining and dashing (punning off of 無線 (musen, “wireless”) with the sense of 無銭 (musen, “money-less”)) / radiation (when used as part of a compound)

a certain one, particular one, specific one

specify, identify, determine

reception of a signal, such as a broadcast signal / reception of a communication, such as an email or telegraph / reception of information

receive a signal / receive a communication / receive information

radio cassette, tape recorder

a transistor radio

radio control

to be on the same wavelength