thru or through meaning

Short answer: "through" is the proper, standard spelling in Australia; "thru" is the casual, signboard-and-text-message variant borrowed from the US.

Both can mean moving from one side to the other or going via something, but use "through" in any formal writing, emails to the boss, and school assignments.

"Thru" fits informal notes and signs like "drive-thru", yet looks wrong in idioms such as "see it through" or "through and through".

When in doubt, choose "through" and you’ll sail right through any pedant’s inspection.