| 1 | German | Ökologie | ecology |
| 2 | German | öko- | eco- |
| 3 | Ancient Greek | οἶκος | house or dwelling place; estate, inheritance;... |
| 4 | Ancient Greek | -λογία | Base for nouns denoting the study of something,... |
| 5 | Ancient Greek | λόγος | That which is said: word, sentence, speech,... |
| 6 | Ancient Greek | λέγω | I put in order, arrange, gather; I choose, count,... |
| 7 | Proto-Indo-European | leǵ- | to gather, collect, with derivatives meaning to... |