What does 'yoga' mean in the Bhagavad Gita?

In popular usage, "yoga" usually means physical postures — a studio class of stretches and poses. The Bhagavad Gita uses the word for something different and older: a discipline of the mind applied to action, not a form of exercise. Krishna gives two back-to-back definitions in chapter 2. In verse 2.48, he tells Arjuna to "perform action, being steadfast in yoga, abandoning attachment, and balanced in success and failure" — and states directly, "samatvam yoga uchyate," evenness of mind is called yoga. The point is that yoga names a quality of inner steadiness maintained while acting, not withdrawal from action. Two verses later, in 2.50, Krishna adds a second definition: "yogah karmasu kaushalam" — yoga is skill in action. Read together, the two verses describe the same discipline from opposite ends: 2.48 defines yoga by the equanimity it protects (indifference to outcome), while 2.50 defines it by the competence it produces (acting well because the mind isn't destabilized by anxiety over results). The word itself comes from the Sanskrit root yuj, "to yoke" or "unite," and the Gita later develops several paths that all count as yoga in this sense — karma yoga (action without attachment to fruits, chapter 3), jnana yoga (knowledge, chapter 4), and bhakti yoga (devotion, chapters 9 and 12) — treating them as different routes to the same union rather than as competing systems. The postural practice familiar in the West (hatha yoga) developed centuries later as its own specialized branch and isn't what these founding verses are describing.