The word "synod" comes from:
SYN= "together", "alike"
ODOS= "way", "travel"
It means, literally, to "share the same way" and is used as such in the New Testament. For example, when Our Lord's family were returning from Jerusalem for the Passover when He was twelve, the group of kinsmen travelling together are referred to as a "synod":
"But they, supposing him to have been in the company (synod), went a day's journey; and they sought him among their kinsfolk and acquaintance." (Luke 2:44)
And again, those who travelled with Saul on the road to Damascus when he was struck down were also a "synod":
"And those who journeyed with him (synodeuontes) stood speechless, hearing a voice but seeing no one" (Acts 9:7)
What is interesting to note is that before our Faith was called "Christianity" it was called "The Way":
"About that time there arose a great disturbance about the Way." (Acts 19:23)
"I persecuted the followers of this Way to their death, arresting both men and women and throwing them into prison,"(Acts 22:4)
"Then Felix, who was well acquainted with the Way, adjourned the proceedings. "When Lysias the commander comes," he said, "I will decide your case."" (Acts 24:22)
Therefore a meeting of those who follow The Way ("odos") is, technically, a "Synodos" (Synod).