/ˈeməˌserē/
Noun, pl. Emissaries
1. A venous channel in the skull. (wiktionary.org)
2. Any of the veins that pass through apertures in the skull and connect the venous sinuses of the dura mater with veins external to the skull. (merriam-webster.com)
3. Applied to the veins which pass out of the cranium through apertures in its walls. (biology-online.org)
4. Valveless veins which normally drain from the dural venous sinuses into veins that lie outside the skull (external veins). However, because they are valveless, pus can flow into the skull through them as well, making them a possible route for transmission of extracranial infection to get into the skull. (wikipedia.org)
Word origin: 1620s, from French émissaire (17c.) or directly from Latin emissarius, literally “that is sent out,” from emissus, past participle of emittere “send forth.”