Avocation

An avocation is an activity that someone engages in as a hobby outside their main occupation. There are many examples of people whose professions were the ways that they made their livings, but for whom their activities outside of their workplaces were their true passions in life. Occasionally, as with Lord Baden-Powell and others, people who pursue an avocation are more remembered by history for their avocation than for their professional career.

Many times a person's regular vocation may lead to an avocation. Many forms of humanitarian campaigning, such as work for organizations like Amnesty International and Greenpeace, may be done by people involved in the law or human rights issues as part of their work.

Many people involved with youth work pursue this as an avocation.

But yield who will to their separation,
My object in living is to unite
My avocation and my vocation
As my two eyes make one in sight.
Only where love and need are one,
And the work is play for mortal stakes,
Is the deed ever really done
For heaven and the future's sakes.

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Wikipedia