'Looped' means something that is made into a loop or circle. For example, if you take a piece of string and twist it around to make a circle, you have looped the string.
You pronounce 'looped' like this: 'looped' rhymes with 'souped'.
The word 'looped' comes from the word 'loop', which has been used in English since the 14th century. It originally meant a 'bent' or 'curved' shape.