Definition of portolan in English:


(also portolano)

nounportolans, portolanos

  • A book of sailing directions with charts and descriptions of harbours and coasts.

    • ‘From early times, charts called portolans (harbor guides) were available to provide details required by the coastline-hugging sailor - depth of the water, location of treacherous rocks, special landmarks, et cetera.’
    • ‘In its purest form, the portolan chart was a highly functional tool for navigation whether in the contained arena of the Mediterranean or later in the open oceans of the world.’
    • ‘On an oceanic voyage, however, especially at higher latitudes, the converging meridians on the physical globe conflicted with the parallel meridians shown on the traditional portolan chart.’
    • ‘Nonetheless, in this period the portolan chart remained very much centred on the Mediterranean and destinations easily reached from there.’
    • ‘The earliest portolan maps covered the Mediterranean and Black Sea and showed wind directions and such information useful to sailors.’


Mid 19th century from Italian portolano, from porto ‘harbour’.