Cannelure (fluting)

Cannelures are the vertical shallow grooves in a colonne (column).
Although well known from Greek and Roman columns, they are also used in roman (Romanesque) columns.
In the picture the (Roman) mauseleum in Saint-Remy-de-Provence (13).
See also pilastre cannelé.

Mausolée - Saint-Remy-de-Provence