No, these aren’t what you might wear for pants, and you will be hard-pressed (pardon the pun) to find them in white (though blue is not unusual).
The lees (pronounced like the jeans) are the dead yeast cells, grape seeds, pulp, stems, skins, and tartrates that separate from the juice during wine making and aging.
When there’s “stuff” at the bottom of the bottle, it’s referred to as sediment or dregs; when you’re discussing the technical aspects of the winemaking, it’s called “the lees” — as in, “this wine was left on the lees for two months, blah blah blah”.
Some wines (usually white) are left in contact with their lees to increase the complexity and enhance the structure of the finished wine. By leaving the juice to remain on top of the lees (and/or occasional stirring) after fermentation, all the dead yeast and skins, etc., can provide additional flavors, body, and richness. After a predetermined amount of time “on the lees”, the juice will then be “racked” — a.k.a., moved to a new container (barrel, tank, etc.) — with the lees left behind.
An example of a wine left on the lees is Muscadet “Sur Lie”; many white wines in the higher price ranges are also left on the lees — it’s a common tactic for ageable whites and Champagnes.
You wrote “Some wines (usually white) are left in contact with their lees to increase the complexity and enhance the structure of the finished wine. ” Sorry but it is the red wines “that are usually left on the lees ” to increase the complexity and enhance the structure of the finished wine.
white wines are very rarely left on the lees. If white wines are left on the lees they can end up with a lot of tannin which would make the white wine less pleasant .
The extracted tannin that comes from the lees is what makes the red wines last longer and in fact less drinkable when they are very young; except for some styles like a Beaujolais. White Zins are an example of a lightly pressed red grape from which the juice is is quickly removed from contact with the red grapes resulting in little or no tannin in that wine.
Most white wines are separated from the lees as soon as possible. Red wines are made by allowing them to stay on the lees to extract as much of the color, (especially red grapes) and flavor as possible.