Find an English word which is singular, add an "s" and it becomes plural, and add another "s" it becomes singular again. What is it?

Answer: There are actually 3 correct answers: Caress. Princess. Brass.

More Difficult Riddles with answers

More Difficult Riddles

Find the four digit number in which the first digit is one fourth of the last digit, the second digit is 6 times the first digit, and the third digit is the second digit plus 3. What is it?
Five baby boomer couples each have one child. Each child is a different age than any of the other children. Each child has a favorite toy which is different from any of the other children's favorite toys. Each family eats at only one fast food restaurant. No two women have the same name and no two men have the same name. The children's names are not known. The child who plays with trains is the youngest. Bill's child plays with a GI Joe. Julie's child likes Pokeman. Mike's family eats at Taco Bell. The family of the 4 year old likes Kentucky Fried Chicken. The oldest child is four years older than Marie's child. The child who plays with Barbie is 8 years old. The child with the age is in the middle, has a mother named Marie. The child in the family that eats at McDonalds has a two year age difference with Larry's child. Carol is the mother in the family that eats at Dairy Queen. The child that plays Nintendo likes Burger King. Steve's child is two years apart in age from the child of the family that eats at Kentucky Fried Chicken. The child that plays with trains is two years apart from the 6 year old. The child that eats at McDonalds is two years older or younger than Regina's child. Lisa's child is 10. Who is married to George?
Five men were eating apples, A finished before B, but behind C. D finished before E, but behind B. What was the finishing order?
Flat as a leaf, round as a ring; Has two eyes, can't see a thing. What is it?
Fuels backyard get-togethers
George, Helen, and Steve are drinking coffee. Bert, Karen, and Dave are drinking soda. Is Elizabeth drinking coffee or soda?
George, Helen, and Steve are drinking coffee. Bert, Karen, and Dave are drinking soda. Using logic, is Elizabeth drinking coffee or soda?
Gets rid of bad ones, short and tall. Tightens when used, one size fits all.
Golden treasure I contain, Guarded by hundreds and thousands. Stored in a labyrinth where no man walks, Yet men come often to seize my gold. By smoke I am overcome and robbed, then left to build my treasure anew
Green arrows grow out of my sides. I go from yellow to white. My babies fly in the wind. What am I?
Halo of water, tongue of wood. Skin of stone, long I've stood. My fingers short reach to the sky. Inside my heart men live and die.
Hard to catch, easy to hold. Can't be seen, unless it's cold