This is the 106th most frequent Thai word.
ต
The Thai letter "ต" (To Tao) is a consonant in the Thai alphabet, representing the "t" sound.
Here, "ตา" (ta) is used metaphorically to describe the color as tiger eye-like.
รถคันนั้นมีสีตาเสือ
That car is tiger-eyed colored.
In this sentence, "ตา" (ta) refers to the anatomical eyes.
เขามีตาสีฟ้าสดใส
He has bright blue eyes.
Here the suffix "ตา" attaches to create its meaning as part of a term for an elderly family member.