The word 先生 is formed through a direct conceptual combination of its two components: 先 (xiān), meaning "first" or "earlier", and 生 (shēng), meaning "born" or "life". It originally and quite literally described someone who was "born earlier", i.e., an elder, and by natural extension, this notion of seniority evolved to convey respect for someone of greater experience or knowledge, such as a teacher. Over centuries, this core idea of a venerable person who is "first in life" (in terms of age or wisdom) generalized further to become a standard, polite form of address for a man, equivalent to "Mister".