What is a community TLD?
A community TLD is a top level domain that is operated for the benefit of a clearly delineated community. Community TLDs were first introduced as an application type during ICANN's New gTLD Program. According to the program, applicants could apply as a "Community-Based Delegation" and they would be given priority for their TLD if there were to be an auction due to multiple applicants.
An example of a new TLD that was applied for as a community TLD is .SCOT, which represents Scottish people, businesses, and culture online (Scotland is considered part of the United Kingdom and does not have its own ccTLD and is under .UK).
Please note that although there were many community TLD applicants, not all were successful as "Community-Based Delegations" due to ICANN's strict requirements for what that meant. All TLDs that might be considered community TLDs are also considered gTLDs.