When we’re talking about words that end in the letter combinations -cede, -sede, and -ceed, one fact should supersede all the others: the word supersede is currently the only English word that ends with -sede. This word is a verb meaning “to take the place of” – and it’s possible that over time the spelling supercede may supersede the current spelling (some dictionaries now show both versions). However, for now we recommend that you use the correct spelling, and use -cede for words such as precede, secede, concede, recede, etc.
Why is there this difference in spelling? The answer is in the history of the words (their etymology). Supersede comes from the Latin prefix super- (“above”) and root word sedere (“to sit”). Traditionally, someone who “sits above” someone else replaces them in authority or position. All of the other words that end in -cede derive from the Latin root word cedere instead, which means “to go.” Therefore, adding prefixes to this root we get “to go before” (pre-), “to go apart” (se-), “to go back” (re-), and so on. In general, other than the word supersede as discussed above, any word that ends in the sound SEED is spelled with -cede.
Of course, since this is the English language there are exceptions to this rule. These three words are spelled -ceed instead:
Although these three words also come from the Latin root word cedere (proceed = “to go forward” / exceed = “to go above” / succeed = “to go after”) their spellings are different. This is due to the fact that they became part of the English language at about the same time, in the 14th century, and so were all governed by the rules of spelling in Old French. Words such as precede were later added to the English language from Middle French, which had different spelling rules.
We hope we’ve planted a few “seeds” of curiosity in you about word origins and their connection to spelling!