'Instillation' definitions:

Definition of 'instillation'

From: WordNet
noun
The introduction of a liquid (by pouring or injection) drop by drop [syn: instillation, instillment, instilment]
noun
A liquid that is instilled drop by drop

Definition of 'Instillation'

From: GCIDE
  • Instillation \In`stil*la"tion\, n. [L. instillatio: cf. F. instillation.] The act of instilling; also, that which is instilled. --Johnson. [1913 Webster]