WordNet sense 1 (flattened laterally along the whole length (e.g., certain leafstalks or flatfishes)):

WordNet sense 2 (of relatively small extent from one surface to the opposite or in cross section):

WordNet sense 3 (pressed tightly together):

WordNet sense 4 (used especially of mouth or eyes):

WordNet sense 5 (capable of being compressed or made more compact):