An Etymological Dictionary of the German Language/Annotated/lehnen
lehnen (1.), verb, ‘to lean, recline’; it combines Middle High German lënen, linen, intransitive, ‘to rest (on),’ and (through the medium of Middle German) Middle High German leinen, transitive, ‘to lean,’ Old High German linên, earlier hlinên, intransitive, and leinen, hleinen, transitive; corresponds to Anglo-Saxon hlinian, hleonian, intransitive, and hlœ̂nan, transitive, ‘to lean.’ The real stem is hli, the n is a verbal suffix (in Lehne, however, corresponding to Greek κλί-νη, a nominal suffix). The graded form of hlī̆, hlai, has been preserved in Leiter; it also existed in an Old Teutonic *hlaiwaz, *hlaiwiz, neuter, ‘hill’ (Gothic hlaiw, Anglo-Saxon hlœ̂w, Old High German lêo for hlêo), as well as in Gothic hlains, masculine, ‘hill,’ Old Icelandic hlein, feminine, ‘projecting rock.’ The root hlī̆, unpermutated klī̆, appears in the non-Teutonic languages with numerous cognates; Greek κλἷ-νω, ‘to lean,’ κλἷ-μαξ feminine, ‘ladder, stairs’ (compare Leiter), κλῖ-νη, ‘couch,’ κλι-σία, ‘conch, easy-chair, tent’ (compare Gothic hlei-þra, feminine, ‘tent’), κλι-τύς, ‘hill,’ κλῖ-τος, κλίτος, neuter, ‘hill’ (compare Modern High German Leite, feminine, Old Icelandic hlíþ, feminine, Anglo-Saxon hlĭþ, neuter, ‘hill’); Latin clinare, ‘to incline,’ clivus, masculine, ‘hill,’ with which are allied Lithuanian szlýti, ‘to incline to one side,’ szlëti, ‘to lean against,’ szlaítas, ‘slope.’ Hence, according to these allied meanings, the idea is ‘to rise gradually, assume a wry form or a slanting position.’
lehnen (2.), verb, ‘to lend,’ from Middle High German lêhenen, Old High German lêhanôn, ‘to bestow as a fief, lend’; compare Lehen, and further also leihen; allied to Anglo-Saxon lœ̂nan (preterite lœ̂nde), English to lend.