Longman Dictionary of Contemporary English
text message
noun
EXAMPLES FROM CORPUS
▪ He shows her a text message sent by Emily asking how the field trip is going.
▪ If the software detects unusual activity on an account, it will send a text message to the mobile phone.
Wiktionary
text message
n. A brief electronic message sent between mobile phones. vb. (context transitive or intransitive English) To transmit a text message.