1) Singlet 2) Tee 1) Singlet 2) Undergarment 3) Vest 4) Where part of this is 
An undershirt is an article of underwear worn underneath a dress shirt intended to protect it from body sweat and odors. It can have short sleeves or be sleeveless. The term most commonly refers to upper-body wear worn by males. It also makes dress shirts less transparent. It can also be worn during winter months as an extra layer of warmth. ==His...
• (n.) A shirt worn next the skin, under another shirt; -- called also undervest.
vest
a collarless, usually pullover undergarment for the torso, usually of cotton and either sleeveless and low-cut or with sleeves, worn chiefly by men and children.