All three are adjectives (as is itsy bitsy).
All three mean very small.
But unless you are talking to someone under 3 years of age, use only tiny.
Teenie (also spelled as teeny) and teensy and itsy bitsy are all cutesy informal words used with children. Very small children.
TEENIE – TEENSY – TINY
FYI is an acronym, and an acronym is a word formed by combining the first letters of each word of a name, such as NATO (North Atlantic Treaty Organization) that is frequently seen in the news. Another one you probably know is AIDS, which is an acronym for Acquired Immune Deficiency Syndrome. Sometimes acronyms are pronounced as a word as in NATO and AIDS, and sometimes the letters are pronounced individually, such as FYI (for your information). And most of the time they are not even pronounced, as they are used mostly in social media, business communication and Internet. But we do hear CNN (Cable News Network) reporters saying ASAP frequently, which means As Soon As Possible and is hard to pronounce.
Sometimes acronyms become words, such as the word scuba. Everybody knows that word, but few know it started out as an acronym for Self-Contained Underwater Breathing Apparatus.
Another acronym that became a word is laser, which began as the acronym Light Amplification by Stimulated Emission of Radiation. Most of us are very pleased that these two words became acronyms.
For now, try to incorporate FYI and ASAP into your daily communications, and don’t spend too much time remembering what AIDS and LASER and SCUBA really mean. But you should be able to recognize NATO as it has become a big issue in North America and Europe.
Here are six business acronyms that you should know if you are a businessperson, and maybe aspire to if you are in middle management. Which one would be the lowest stress and the highest salary?