Yes, "tacking" is the correct term for this cycling technique...although colloquially you'll also hear it referred to as "paperboying", implying that that's the way the kid who used to deliver newspapers on his bike would ride, zigzagging across the street.

fwiw it's not considered good form to tack up hills if you're riding with other cyclists; getting easier gearing and/or learning to spin the gears you have so that you can climb in a straight line will make you a safer, more predictable cyclist.