a garment: a piece of clothing, especially the loose outer robe worn over the tunic
In the ancient Mediterranean world a person typically wore two layers: a tunic next to the body and a larger wrap thrown over it. This word names the outer wrap, and by extension a piece of clothing in general.
The two senses are really one idea seen up close and far off. Up close it is one specific item, the cloak or mantle that a person could draw around them, lay aside, throw off, or lose. Stepped back, especially when the word is plural, it simply means a person's clothes, their whole outfit.
Which sense is in view is usually clear from the scene. When the cloak is set against the tunic, or someone touches its edge or flings it off, the specific outer robe is meant. When people spread their clothes on the road or strip a man of his clothing, the general sense of garments is at work.