por·ta·men·to 
(pôr′tə-mĕntō)
(pôr′tə-mĕntō)n. pl. por·ta·men·ti (-tē) or por·ta·men·tos
A smooth uninterrupted glide in passing from one tone to another, especially with the voice or a bowed stringed instrument.
[Italian, from portare, to carry, from Latin portāre; see per-2 in the Appendix of Indo-European roots.]