Definition - What does Harvest mean?
The "harvest" is the process by which wine grapes are picked. This may be done by hand or mechanically, utilizing specialized mechanical picking machines. It is also a term used to describe the period when the grapes are removed from the vines - "the harvest season". In the Northern Hemisphere, harvest typically begins around September, and in the Southern Hemisphere, it begins in March.
WineFrog explains Harvest
Harvest can also be synonymous with crush. It is referred to as "crush", because once the grapes go through sorting process, they then go through a process known as crushing so that the juices can run free. This allows for even fermentation.
In general, the term harvest refers to the time period that grapes are picked from the vineyards. Each year it varies. Some harvests may begin early, some may begin late, depending on the conditions within the growing season. Each winemaker and/or viticulturist determine when grapes are ready for harvest.