These three terms get used interchangeably, but they're not the same thing.
Waxing is the most basic service. Technicians apply a layer of glide wax to the base of your skis, which reduces friction against the snow. Wax wears off over time, especially on abrasive or icy snow, so it needs to be reapplied regularly throughout the season. A basic wax is quick, affordable, and something you can even tackle yourself — we've put together a guide to DIY waxing and edge tuning with VOLA tools if you want to give it a go.
An edge tune is about your edges, the thin strips of metal that run along the sides of your bases. Sharp edges grip the snow when you carve or brake. Dull or burred edges feel loose and unpredictable, especially on hard pack and ice. A tune involves filing and sharpening the edges to a consistent bevel angle, then de-burring them for smooth contact. Edge work takes more time and skill than waxing.
A full service combines both: a base grind (using a stone grinding machine to resurface the base material and remove deep gouges), a full edge tune, and a fresh wax. This is the most thorough option and the one your skis genuinely need at least once a season.