Tokusatsu (特撮), sometimes shortened to Toku, is a Japanese term that applies to any live-action film or television drama that usually features superheroes and makes considerable use of special effects (tokusatsu literally translates as "special filming" in Japanese).
Tokusatsu is the genre that Super Sentai belongs to. Other popular Tokusatsu franchises are the Kamen Rider (1971-) and Metal Heroes (1982-1999) series. Also, a minor Toku show in the 70s, Ninja Captor, was once classed as the second Super Sentai series.
While Super Sentai has often teamed up its series with another, it has only crossed over with another Tokusatsu franchise three times. The first was Kamen Rider Decade: Shinkenger World, the second was Kaizoku Sentai Gokaiger vs. Gavan, and the third was Super Hero Taisen, which brought nearly all the Riders and Sentai teams together.
There have been many non-Japanese adaptations of tokusatsu.
A major influx of tokusatsu adaptations came to American television in the 1990s, starting in 1993 with Saban Entertainment's purchase of footage from Toei's sixteenth installment of the long-running Super Sentai series, Kyoryu Sentai Zyuranger to become Mighty Morphin' Power Rangers and start the popular Power Rangers franchise. Subsequent seasons of Super Sentai would be adapted in similar fashion for later seasons of the show. An adaptation of footage from Choujinki Metalder, Jikuu Senshi Spielban, and Uchuu Keiji Shaider from the Metal Hero series, became VR Troopers in 1994.
There followed an adaptation of the ninth series in the Kamen Rider franchise, Kamen Rider Black RX, into Saban's Masked Rider, which was introduced in a crossover with Power Rangers. In 1996 and 1997, Juukou B-Fighter and its sequel B-Fighter Kabuto became Big Bad Beetleborgs and its sequel Beetleborgs Metallix. Some costumes from these shows would later be used in Power Rangers most notably when costumes for the Beetleborgs were used as the Machine Empire Generals in Forever Red.
Most recently, the third Heisei Kamen Rider series Kamen Rider Ryuki had been adapted into Kamen Rider: Dragon Knight. Unlike Masked Rider, this series had no connection with Power Rangers, being conduced by Adness Entertainment.
Aside from Power Rangers, other Sentai-esqe shows have appeared in France and Thailand, France Five and Sport Ranger respectively. Unlike, Power Rangers, these shows weren't actually adaptations as they, despite being based off Sentai, were entirely new series.
Other popular Tokusatsu included Pretty Guardien Sailor Moon.