A steel guitar (Hawaiian: kīkākila) is a guitar played while moving a steel bar or similar hard object against plucked strings. The bar itself is called a "steel" and is the source of the name "steel guitar". The instrument differs from a conventional guitar in that it has no frets—but markers that look like frets. Conceptually, it is somewhat akin to playing a guitar with one finger (the bar). Known for its smooth, gliding glissandi over every pitch between notes, the instrument can produce a sinuous crying sound and deep vibrato emulating the human singing voice. Typically, the strings are plucked (not strummed) by the fingers of one hand, while the steel tone bar is pressed lightly against the strings and moved by the opposite hand.
The idea of creating music with a slide of some type has been traced back to early African instruments, but the modern steel guitar was conceived and popularized in the Hawaiian Islands. The Hawaiians began playing a conventional guitar in a horizontal position across the knees instead of flat against the body, using the bar instead of fingers. Joseph Kekuku developed this manner of playing a guitar, known as "Hawaiian style", about 1890 and the technique spread internationally.