The use of a mobile phone to send text messages via SMS(noun)
Wiktionary.org : Text is available under the Creative Commons Attribution-ShareAlike License
Use "texting" in a sentence
"By texting a code word such as "Haiti" to a designated number, people can donate $5 or $10 that will be added to their phone bills."
"The heavier use of trains and subways, where texting is allowed but talking often not (as opposed to planes where neither are or driving where talking is safer than texting), also drives the use of text messages."
"When it comes to movie theater etiquette, texting is the new "talking", and just as rude."