The word yoga has become very popular in todays vocabulary, but we understand from the Bhagavad-gita the real definition of the word, and its ultimate goal.

A yogī is greater than the ascetic, greater than the empiricist and greater than the fruitive worker. Therefore, O Arjuna, in all circumstances, be a yogī. (Bg. 6.46)

And of all yogīs, he who always abides in Me with great faith, worshiping Me in transcendental loving service, is most intimately united with Me in yoga and is the highest of all. (Bg. 6.47)

When we speak of yoga we refer to linking up our consciousness with the Supreme Absolute Truth. Such a process is named differently by various practitioners in terms of the particular method adopted. When the linking up process is predominantly in fruitive activities, it is called karma-yoga, when it is predominantly empirical, it is called jñāna-yoga, and when it is predominantly in a devotional relationship with the Supreme Lord, it is called bhakti-yoga. Bhakti-yoga or Kṛṣṇa consciousness is the ultimate perfection of all yogas (from purport to Bg. 6.46)

The culmination of all kinds of yoga practices lies in bhakti-yoga. All other yogas are but means to come to the point of bhakti in bhakti-yoga. Yoga actually means bhakti-yoga; all other yogas are progressions toward the destination of bhakti-yoga. From the beginning of karma-yoga to the end of bhakti-yoga is a long way to self-realization. Karma-yoga, without fruitive results, is the beginning of this path. When karma-yoga increases in knowledge and renunciation, the stage is called jñāna-yoga. When jñāna-yoga increases in meditation on the Supersoul by different physical processes, and the mind is on Him, it is called aṣṭāṅga-yoga. And, when one surpasses the aṣṭāṅga-yoga and comes to the point of the Supreme Personality of Godhead Kṛṣṇa, it is called bhakti-yoga, the culmination. Factually, bhakti-yoga is the ultimate goal (from purport to Bg. 6.47)

full texts and purports