Thirde

Part of speech: adjective, noun

Definitions

1. Archaic form meaning coming after the second in an order or sequence ; one of three equal parts into which something is divided
2. An older spelling for the ordinal placed immediately after second in a series ; a single portion when something is split into three equal shares
3. Describing the position right after the second item in a row ; denoting any of three equal portions that make up a whole

Etymology: "Thirde" is simply an older spelling of "third", the ordinal that comes after "second" and means one of three equal parts. Its ancestry runs back to a prehistoric Indo-European root, "tr̥tyós, which was reshaped in the Germanic branch into "þridjô and then into Old English "þridda". The Middle English spelling "thirde" or "thridde" carried that form forward, and the "th" sound at the start is the same one that still opens the word today. The word's most notable feature is how the "r" moved. In the older form the "r" sat before the "d" in a different place, and the sound shifted during the centuries that followed, so the "r" and the vowel traded positions compared with the earlier root. This kind of reordering, called metathesis, is common in English and explains why "third" looks less like "three" than one might expect, even though the two words are related.