List of Ham Radio terms:

The basics:
This is, by far, nothing close to the amount of terms use in Ham radio, however, these are some of the most used and ones you will hear getting on the air for the first time.

All the most used terms in Alphabetical order:

HAM Term Meaning How to Use
73 Best wishes, have a good one 73, this is [your call sign]
Roger Got it, understood Roger that
Copy Understand Copy that
QSO Conversation I just had a QSO with another ham in my area
Clear Good-bye / Off the air This is [your call sign] clear
Mobile Traveling [Your call sign] mobile
Monitor Listen This is [your call sign] monitoring
QSY Changing frequency I am going to QSY over to '62
Double Talking simultaneously You two doubled with each other
Step on Talk over I apologize, I stepped on you
PTT Push-To-Talk Push your PTT button to talk
HT Handy Talkie My radio is an HT
Rubber Duck Stock antenna that usually comes with your HT radio I'm using a rubber duck
Stand by Wait / Pause This is [your call sign] stand by
NET On-Air Gathering The NET is at noon
In and Out Offline Check-In This is, [your call sign], I am in and out
Elmer Ham Radio Mentor John is my Elmer
Final Concluding Transmission I'll be clear on your final
Kerchunk Keying up silently All I could hear is someone kerchunking
Picket Fencing Fluttering transmission Your signal is picket fencing
Ragchew Shooting the breeze We're just rag chewing right now
Shack Your radio room My shack is downstairs
Silent key / SK Deceased Ham My Dad is a silent key
Full Quieting No background noise You're full quieting in the repeater
Relay Pass a Message Could you please relay?
Key Up Transmit Key up when you are ready to speak
Unkey Stop Transmitting Release the PTT button
Ticket Ham Radio License When did you get your ticket
73 -- Ham lingo for "best regards.":

Used on both phone and CW toward the end of a contact. The first authentic use of 73 is in the publication The National Telegraph Review and Operators' Guide, first published in April 1857.
At that time, 73 meant "My love to you!" In the National Telegraph Convention, the numeral was changed to a friendly "word" between operators.
In 1859, the Western Union Company set up the standard "92 Code." A list of numerals from one to 92 was compiled to indicate a series of prepared phrases for use by the operators on the wires. Here, in the 92 Code, 73 changes to "accept my compliments," which was in keeping with the florid language of that era. Over the years from 1859 to 1900, the many manuals of telegraphy show variations of this meaning.
Dodge's The Telegraph Instructor shows it merely as "compliments." The Twentieth Century Manual of Railway and Commercial Telegraphy defines it two ways, one listing as "my compliments to you;" but in the glossary of abbreviations it is merely "compliments."
Theodore A. Edison's Telegraphy Self-Taught shows a return to "accept my compliments." By 1908, however, a later edition of the Dodge Manual gives us today's definition of "best regards" with a backward look at the older meaning in another part of the work where it also lists it as "compliments." "Best regards" has remained ever since as the "put-it-down-in-black-and-white" meaning of 73 but it has acquired overtones of much warmer meaning.

Today, amateurs use it more in the manner that James Reid had intended that it be used --a "friendly word between operators."