Noun
guitar whose steel strings are twanged while being pressed with a movable steel bar for a glissando effect
Source: WordNetHowever, Hawaiian guitar often refers to slack key guitar, played in the conventional or Spanish position, using a conventional fretted guitar in various open tunings, generally with the strings tuned considerably lower than usual. Source: Internet
Thus, the lap steel guitar is sometimes known as the Hawaiian guitar, particularly in documents from the early 20th century, and today any steel guitar is frequently called a Hawaiian steel guitar. Source: Internet