sandhi

[suhn-dee] /ˈsʌn di/
noun, plural sandhis. Linguistics
1.
morphophonemic alternation, especially as determined by phonetic environment, as in dontcha for don't you.
Origin
1800-10; < Sanskrit saṃdhi joining, juncture
British Dictionary definitions for sandhi

sandhi

/ˈsændɪ/
noun (pl) -dhis
1.
(linguistics) modification of the form or sound of a word under the influence of an adjacent word
Word Origin
from Sanskrit samdhi a placing together, from sam together + dadhāti he puts