Lambert

Lambert is a surname and given name of Germanic origin, derived from elements meaning “land” and “bright.” It is common in various European languages and has spread to English-speaking countries.

Johann Heinrich Lambert (1728–1777) was a Swiss mathematician, physicist, and astronomer whose work influenced optics, geometry, and the study of perception. He formulated Lambert’s cosine law, describing how the apparent brightness of a diffuse reflector varies with the angle of incidence, and contributed to early ideas about shadows and color. The Lambert W function, the inverse of the function f(W) = W e^W, is named in his honor and is used in mathematics and physics.

Lambert’s name also appears in cartography and mathematical functions through Lambert projections, including the Lambert cylindrical equal-area projection, the Lambert azimuthal equal-area projection, and the Lambert conformal conic projection, all developed for mapmaking and spatial analysis.

In photometry, the lambert is a historical non-SI unit of luminance once used in older literature; modern practice uses the candela per square meter.

Beyond science, Lambert remains a common surname and given name and is associated with various places and communities, reflecting its geographic and cultural roots.