Bow (music)
When string players talk about “putting in the bowing” they mean: writing in the music for each note whether it is played with an upbow or downbow.   A downbow is when the player starts at the heel (the end that he is holding) and finishes at the tip.  An upbow is when the bow travels in the direction  tip to  heel.  A player does not always have to use “whole bows” (from the heel to the tip).  In fast music he may only use a small part of the bow.  A downbow feels stronger than an upbow, so it is usually used for the first beat of the bar.  Downbows and upbows may be used for alternate notes, but often two or more notes are taken in one bow-stroke.  This is shown in the music by a slur (a short curved line like a phrase mark over or under the notes to be slurred).