"design based on systems simulating or utilizing patterns and features observed in natural ecosystems," by 1978, from permanent + -culture, in this case abstracted from agriculture.
Entries linking to permaculture
permanent adj.
"enduring, unchanging, unchanged, lasting or intended to last indefinitely," early 15c., from Old French permanent, parmanent (14c.) or directly from Latin permanentem (nominative permanens) "remaining," present participle of permanere "endure, hold out, continue, stay to the end," from per "through" (from PIE root *per- (1) "forward," hence "through") + manere "stay" (from PIE root *men- (3) "to remain").
Related: Permanently. As a noun meaning "permanent wave," by 1909. Of clothing, permanent press, in reference to a process designed to produce lasting creases in fabric," is attested from 1964.
agriculture n.
mid-15c., "tillage, cultivation of large areas of land to provide food," from Late Latin agricultura "cultivation of the land," a contraction of agri cultura "cultivation of land," from agri, genitive of ager "a field" (from PIE root *agro- "field") + cultura "cultivation" (see culture (n.)). In Old English, the idea could be expressed by eorðtilþ.