From Longman Dictionary of Contemporary Englishin touch (with somebody)in touch (with somebody)talking or writing to someoneWe’ll get in touch (=start talking or writing to you) as soon as we know the results of the test.Can I have your phone number in case I need to get in touch with you?Bye. I’ll be in touch.Are you still in touch with John (=are you talking to him regularly)?I’m in close touch with Anna.stay/keep in touch (=keep writing or talking, even though you do not see each other often)Anyway, we must stay in touch.I met him when I worked in Madrid, and I’ve kept in touch with him ever since.I lost touch with (=stopped writing or talking to) Julie after we moved.I can put you in touch with a local photography club (=give you their address or phone number so you can talk to them).USAGE: In touch, in contact• If you stay/keep in touch or keep in contact with someone, you keep writing to them or calling them: I hope you'll keep in touch while you're away.• If two things are in contact or come into contact, they touch each other: Make sure that the two wires don't come into contact.✗Don’t say in touch in this meaning. →touch
Examples from the Corpus
in touch (with somebody)• Tell your people who I am, that I will be in touch, I will be waiting.• Promised her he would be in touch, and to be with her for the birth of their baby.• Watching us, our children learn that people write to keep in touch, and that letters are usually answered.• Over the years, we kept in touch by telephone and he was a faultlesscorrespondent.• Underneath it all was the desire to stayin touch with Sophie.• Lots of travelingdads and moms are now using e-mail to stay in touch.• I made a lot of new friends, some of whom are still in touch.• The few people I treasure were in touch and I told them exactly what was wrong.