MarWinThe Seiko 5 sports is in reference of a very rich watch history for Seiko. In general, it has evolved over time to indicate relatively affordable casual watches that are rugged enough for activities. Seiko has many sub-brands in addition to seiko 5, prospex for example is their middle range sporty watches, grand seikos are the high end watches, but they also have other brand names not recognized often: pulsar and j spring ( cheap fashion watches), credor ( ultra high end), alba. they even recently purchased orient watches.
some history of the seiko 5:
https://www.seiko.dk/5sports/seiko5story/index.html