The word "HELO" is often used as an acronym for "Helicopter Landing Officer" in military and aviation communities. However, it can also be used as a shortened form of the word "Hello", which is a greeting used to acknowledge or welcome someone. If you are looking for synonyms for "HELO" that are related to the greeting, you can use words such as "hi", "hey", "greetings", "salutations", or "howdy". These words can be used interchangeably and are suitable for a variety of situations when you want to say hello to someone.