Something published for others to meet. Also an upright that bears weight, and to send onward.
Latin postis (an upright, doorpost), and separately positus (placed), both related to ponere (to place); a thing published for others to meet, an upright that bears weight, and the act of sending onward all share one root in something fixed or set in place.
Something published for others to come across, an upright that bears weight, or the act of sending a thing onward — three senses sharing one image of something fixed in place.