tlilxochitl.

Headword: 
tlilxochitl.
Principal English Translation: 

vanilla orchids (literally, black flowers) (see Karttunen)

Orthographic Variants: 
tlilxuchitl
IPAspelling: 
tɬiːlʃoːtʃitɬ
Alonso de Molina: 

tlilxuchitl. ciertas vaynicas de olores.
Alonso de Molina, Vocabulario en lengua castellana y mexicana y mexicana y castellana, 1571, part 2, Nahuatl to Spanish, f. 148r. col. 1. Thanks to Joe Campbell for providing the transcription.

Frances Karttunen: 

TLĪLXŌCHITL vanilla orchid / ciertas vainicas de olores (M), la vanilla, fruto americano conocido en toda la Europa (R) [(1)Rp.150]. Although this literally means ‘black flower’ the blossom is yellow, while the pod, or vanilla bean, is black. R fails to mark the long wowels. See TLĪL-LI, XŌCHI-TL.
Frances Karttunen, An Analytical Dictionary of Nahuatl (Norman: University of Oklahoma Press, 1992), 308.

Attestations from sources in English: 

Nonqua onoca in qujnamaca cacaoatl, vej nacaztli, tlilxochitl = Separate were those who sold chocolate, aromatic herbs, and vanilla (central Mexico, sixteenth century)
Fr. Bernardino de Sahagún, Florentine Codex: General History of the Things of New Spain; Book 8 -- Kings and Lords, no. 14, Part IX, eds. and transl. Arthur J. O. Anderson and Charles E. Dibble (Santa Fe and Salt Lake City: School of American Research and the University of Utah, 1951), 67.

themes: 
Flowers
Plants, Trees, Flora