Adder and Personal digital assistant

Adder noun - A person who adds numbers.

Personal digital assistant and adder are semantically related. In some cases you can use "Personal digital assistant" instead a noun "Adder".

Personal digital assistant noun - A lightweight consumer electronic device that looks like a hand-held computer but instead performs specific tasks; can serve as a diary or a personal database or a telephone or an alarm clock etc..

Adder and personal digital assistant are semantically related. You can use "Adder" instead a noun phrase "Personal digital assistant".