Of uncertain etymological origin, the word "shanty" emerged in the mid-19th century in reference to an appreciably distinct genre of work song, developed especially on merchant vessels that had come to prominence in the decades prior to the American Civil War although were found before this. Shanty songs functioned to synchronize and thereby optimize labor, in what had then become larger vessels having smaller crews and operating on stricter schedules. The practice of singing shanties eventually became ubiquitous internationally and throughout the era of wind-driven packet and clipper ships.