means of living; livelihood resources
Refers to the financial resources or material means necessary to sustain one's life; somewhat formal and often used in discussions of economic security.
He works hard every day to earn a living.
The pension alone is not enough to cover the means of living.
Compound of 生活 (livelihood) and 資 (resources, funds), with the possessive particle の linking them. The exact historical derivation is uncertain, but the phrase is a straightforward combination of these elements.