阑 is a bound morpheme (b.f.) meaning 'railing, fence, or balustrade'. It cannot stand alone as a word; you will only encounter it as part of compound words, most commonly 栏杆 (lán gān, 'railing'), 阑尾 (lán wěi, 'appendix'), and the literary 阑珊 (lán shān, 'waning, declining'). When you see 阑 in a text, it is always attached to another character.