Hi lightsandcandy, Stoicism is a philosophy of life in which you strive to be virtuous (the unofficial Stoic motto is often said to be, "virtue is the only good") and you acknowledge that the path to a sense of flourishing is in understanding that while much of life is outside your control, what is very much within your control is how you perceive and respond to the world around you and the events that happen to you.
While many people might think of the popular definition of 'stoicism' as being a state of dour and fatalistic acceptance, the goal of Stoicism is to achieve a Stoic joy that comes with freedom from the negative, or even false-positive, emotions that we inflict on ourselves.
The following quote from Marcus Aurelius gives a sense of the Stoic approach to life:
“Begin each day by telling yourself: Today I shall be meeting with interference, ingratitude, insolence, disloyalty, ill-will, and selfishness – all of them due to the offenders’ ignorance of what is good or evil. But for my part I have long perceived the nature of good and its nobility, the nature of evil and its meanness, and also the nature of the culprit himself, who is my brother (not in the physical sense, but as a fellow creature similarly endowed with reason and a share of the divine); therefore none of those things can injure me, for nobody can implicate me in what is degrading. Neither can I be angry with my brother or fall foul of him; for he and I were born to work together, like a man’s two hands, feet or eyelids, or the upper and lower rows of his teeth. To obstruct each other is against Nature’s law – and what is irritation or aversion but a form of obstruction.”
As a progressing Stoic, I see the above as meaning that I will not get to choose how people behave to me today, but I absolutely do get to choose what I feel in response to those people. The section that reads ...due to the offenders’ ignorance of what is good or evil... speaks to the idea that Stoics believe that 'good' is about living in accordance with 'nature' -- but not nature in the sense of living in a log cabin in a forest, but nature in the sense of the ideal nature of ourselves, and the ideal nature of humans in general.
There is a great deal more to Stoicism than this -- I'd be very happy to talk to you more, or point you to books and resources, if you continue to be interested.