Explicit vs. Tacit Knowledge
Explizites vs. implizites Wissen
Explicit knowledge is knowledge that can be clearly articulated, documented, and passed on, such as an instruction manual. Tacit knowledge, by contrast, is tied to experience and hard to put into words — such as a "feel" for a customer situation. Good knowledge management aims to convert as much tacit knowledge into explicit knowledge as possible.
Source: Nonaka & Takeuchi — The Knowledge-Creating Company (foundational management theory)