the GNU version of the Collaborative International Dictionary of English
n. The dorsal plate of the prothorax in insects. See Illust. of coleoptera.
The Century Dictionary and Cyclopedia
n. The anterior one of the three divisions of the notum of an insect, preceding the mesonotum; the dorsal or tergal section of the prothorax; the upper part of the first thoracic segment or prothoracic tergum.
n. See the adjectives.
Word Usage
"The pronotum is the dorsal plate of the prothorax, forming a wide arc over the propectuses and encircling their pleural plates ventrally ("