1.  viola(n = noun.plant) - any of the numerous plants of the genus Viola;
is a kind of herb, herbaceous plant
is a member of genus viola, viola
has particulars: violet, field pansy, heartsease, viola arvensis, horned violet, tufted pansy, viola cornuta, pansy, viola tricolor hortensis, heartsease, johnny-jump-up, love-in-idleness, pink of my john, viola tricolor, wild pansy

2.  viola(n = noun.plant) genus viola - large genus of flowering herbs of temperate regions;
is a kind of dilleniid dicot genus
is a member of family violaceae, violaceae, violet family

3.  viola(n = noun.artifact) - a bowed stringed instrument slightly larger than a violin, tuned a fifth lower;
is a kind of bowed stringed instrument, string

   A genus of polypetalous herbaceous plants, including all kinds of violets. [1913 Webster]

   An instrument in form and use resembling the violin, but larger, and a fifth lower in compass. [1913 Webster]

viola, n.
1 a an instrument of the violin family, larger than the violin and of lower pitch. b a viola-player.
2 a viol.

Idiom:
viola da braccio a viol corresponding to the modern viola. viola da gamba a viol held between the player's legs, esp. one corresponding to the modern cello. viola d'amore a sweet-toned tenor viol.

viola, n.
1 any plant of the genus Viola, including the pansy and violet.
2 a cultivated hybrid of this genus.

Etymology:
L, = violet

N  musical instruments, band, string-band, brass-band, orchestra, orchestrina, monochord, polychord, harp, lyre, lute, archlute, mandola, mandolin, mandoline, guitar, zither, cither, cithern, gittern, rebeck, bandurria, bandura, banjo, bina, vina, xanorphica, viol, violin, fiddle, kit, viola, viola d'amore, viola di gamba, tenor, cremona, violoncello, bass, bass viol, base viol, theorbo, double base, contrabasso, violone, psaltery, bow, fiddlestick, piano, pianoforte, harpsichord, clavichord, clarichord, manichord, clavier, spinet, virginals, dulcimer, hurdy-gurdy, vielle, pianino, Eolian harp, organ, harmonium, harmoniphon, American organ, barrel organ, hand organ, accordion, seraphina, concertina, humming top, flute, fife, piccolo, flageolet, clarinet, claronet, basset horn, corno di bassetto, oboe, hautboy, cor Anglais, corno Inglese, bassoon, double bassoon, contrafagotto, serpent, bass clarinet, bagpipes, union pipes, musette, ocarina, Pandean pipes, reed instrument, sirene, pipe, pitch-pipe, sourdet, whistle, catcall, doodlesack, harmoniphone, horn, bugle, cornet, cornet-a-pistons, cornopean, clarion, trumpet, trombone, ophicleide, French horn, saxophone, sax, buglehorn, saxhorn, flugelhorn, althorn, helicanhorn, posthorn, sackbut, euphonium, bombardon tuba, cymbal, bell, gong, tambour, tambourine, tamborine, drum, tom-tom, tabor, tabret, tabourine, taborin, side drum, kettle drum, timpani, tympani, tymbal, timbrel, castanet, bones, musical glasses, musical stones, harmonica, sounding-board, rattle, tam-tam, zambomba, reed, tuning fork, triangle, Jew's harp, musical box, harmonicon, xylophone, sordine, sordet, sourdine, sourdet, mute, (iv) PERCEPTION OF SOUND.

genus viola, viola arvensis, viola blanda, viola canadensis, viola canina, viola clef, viola conspersa, viola cornuta, viola d'amore, viola da braccio, viola da gamba, viola ocellata, viola odorata, viola pedata, viola pubescens, viola reichenbachiana, viola rostrata, viola striata, viola sylvatica, viola tricolor, viola tricolor hortensis