The term “extension” comes from the Latin word “extensionem,” which means “a stretching out” or “an extension.” Here’s a detailed chronological breakdown:

1. Proto-Indo-European (PIE)

The PIE root “*ten-” means “to stretch.”

2. Latin

From the PIE root, the Latin verb “tendere” developed, meaning “to stretch.” The noun “extensio” (genitive “extensionis”) comes from the verb “extendere,” which combines “ex-” (out) and “tendere” (to stretch), meaning “a stretching out” or “extension.”

3. Old French (c. 9th to 14th century CE)

The Latin term “extensionem” evolved into Old French “extension,” maintaining the meaning of “a stretching out” or “an enlargement.”

4. Middle English (c. 11th to 15th century CE)

The Old French “extension” was adopted into Middle English as “extensioun,” meaning “a stretching out,” “an expansion,” or “an increase in length or duration.”

5. Modern English (from 15th century CE to present)

The term “extension” evolved into its current form and pronunciation, referring to the act of extending or the state of being extended. It also encompasses meanings such as an addition to a building, an increase in time, or a part that is added to something to enlarge or prolong it.

The word “extension” reflects the concept of stretching out or expanding something, whether in physical space, time, or scope. It is used in various contexts, from architecture and construction to time management and technological applications.