Rabat
The two words you're looking for are "oak" and "earth." "Oak" is a type of tree, while "earth" refers to the planet we live on. Both words fit the criteria of starting with 'o,' having three letters, and five letters, respectively.
Ulan Bator
Drink?
asset
tarsal
Parrot
An Abbot is a holy man beginning with "a" and having five letters.
There are no five letter words starting with the two letters a and j
gentsa
inlet
· Nauru · Nepal · Niger
No, April is not the only month with five letters in its name. Other months that also have five letters include May and June. However, May and June only have three and four letters, respectively, so April is indeed unique in having five letters among the months.