means To tilt or rest at an angle, to depend on something for support, or — in business — to be stripped down to only the essentials with minimal waste.

from From Old English 'hleonian,' meaning to recline or rest at a slant — a cousin of words across the Germanic family for tilting and bending, and possibly distantly related to Latin 'clinare,' to lean. The 'thin, lacking fat' sense comes from a separate Old English word, 'hlǣne,' and the two streams have flowed together so completely that modern 'lean' carries both: the body that tilts and the body without spare flesh. The manufacturing meaning is a 20th-century borrowing of that second sense — 'no excess fat on the system.'