| geological formation | (n) (geology) the geological features of the earth, Syn. formation |
| 系統 | [けいとう, keitou] (n) system; family line; geological formation; lineage; ancestry; (P) #1,225 [Add to Longdo] |
| 地層 | [ちそう, chisou] (n) stratum; geological formation; layer; bed (coal, gravel, etc.); (P) #17,295 [Add to Longdo] |