机缘 refers to a fortunate opportunity or coincidence that feels destined or serendipitous, often with a sense of fate or karmic timing. The term has Buddhist roots (缘 means 'condition' or 'karmic connection'), so it carries a deeper meaning than just 'luck' — it implies that the opportunity arose because the right conditions aligned. You can use it in contexts like meeting someone at just the right moment or stumbling upon a life-changing chance.