Marcato (short form: Marc.; Italian for marked) is a musical instruction indicating a note, chord, or passage is to be played louder or more forcefully than surrounding music. The instruction may involve the word marcato itself written above or below the staff or it may take the form of an accent mark, ?, an open vertical wedge. This is essentially a stressed version of the regular accent indicated by >, an open horizontal wedge: it asks for a greater dynamic accent.
Like the regular accent, however, the Marcato is often interpreted to suggest a sharp attack tapering to the original dynamic, an interpretation which applies only to instruments capable of altering the dynamic level of a single sustained pitch. According to author James Mark Jordan, "the marcato sound is characterised by a rhythmic thrust followed by a decay of the sound"
In jazz big-band scores the marcato symbol usually indicates a note is to be shortened to approximately 2/3 its normal duration, and given a moderate accent.
The instruction marcato or marcatissimo (extreme marcato), among various other instructions, symbols, and expression marks may prompt a string player to use martellato bowing, depending on the musical context.
An example would be from Gavotte in D Major from J. S. Bach (Suzuki Book Volume 3) page 19, Bar 39.
Video Marcato
References
Source of the article : Wikipedia