Meaning

noun a large entrance or reception room or area

noun the people who support some common cause or business or principle or sectional interest

noun a group of people who try actively to influence legislation

originFrom Medieval Latin lobia, lobium, laubia (“a portico, covered way, gallery”), borrowed from Frankish *laubijā (“arbour, shelter”), related to Old English lēaf (“foliage”). More at leaf. Doublet of leaf, lodge, and loggia. Political sense derives from the entrance hall of legislatures, where people traditionally tried to influence legislators because it was the most convenient place to meet them.

Etymology from Wiktionary, CC BY-SA 3.0