Adjust your belt so that it's more comfortable - loosen it. Adjust the t.v settings - to make the picture better by adjusting colour, contrast, sound. Adjust the oven or fridge - adjust the temperatue to make it colder or hotter. Adjust clothing - straighten your clothing after sitting. Adjust your differences - settle something so that an agreement is made.

It has many similar but not synonymous meanings. Plenty of examples here, especially under the heading labeled "thesaurus": http://www.thefreedictionary.com/_/dict.aspx?rd=1&word=adjust