ETIQUETTE for Hats and Caps
When a gentleman “dons” his hat to leave or “doffs” his hat to a lady, his actions are being described by two British colloquialisms that come from contractions of the phrases “do on” meaning “to do”, and the Middle English “doffen”, which became “don off” meaning “to do off”!
Hats are tipped, (or doffed) slightly lifting the hat off your forehead, when meeting a lady (remove your hat if you stop to talk), or to "say" to anyone, male or female – thank you, excuse me, hello, goodbye, you’re welcome or how do you do.
Tipping of the hat is a conventional gesture of politeness. This hat tipping custom has the same origin as military saluting, which came from the raising of medieval Knights face visors to show friendliness.
Hats are worn less now, but at the turn of the 20th century, all adults wore hats whenever they left the house. It was a matter of good personal hygiene, since hats were a protection from industrial dirt.
Hats are removed when inside, except for places that are akin to public streets, like lobbies, corridors, and crowded elevators (non-residential). In a public building (where there are no apartments) the elevator is considered a public area.
You may remove your hat in a public elevator in the presence of a lady and your had must be removed. A gentleman takes off his hat and holds it in his hand when a lady enters the elevator in an apartment house or hotel--any building, which can be classified as a dwelling. He puts it on again in the corridor.
A public corridor is like the street, but an elevator in a hotel or apartment house has the character of a room in a house and there a gentleman does not keep his hat on in the presence of ladies.
Hats are removed for the National Anthem, passing of the Flag and funeral processions, outdoor weddings, dedications, and photographs.
Removed hats are held in hand in such a way that only the outside and never the lining is visible.
In places of worship head coverings are required for both men and women in Muslim mosques, and Sikh temples.
Men are required to cover their heads in Jewish synagogues, but only married women wear hats or scarves representing a display of her increased modesty towards those other than the woman's husband.
The small, round head covering or skullcap worn by men is called a “kippah” which means, “dome” or “cupola”. The Yiddish word for the cap is “yarmulke”. The wearing of the yarmulke is a reminder of humility before God, a mark of respect in a Jewish congregation, and a sign of recognition of something greater above oneself, which is why many male Jews wear a head covering whenever they are awake, with the exceptions of bathing and swimming.
It is acceptable for women to wear hats in Christian churches, (it was once required, but the custom has all but disappeared) but disrespectful for men to wear them.
A woman may leave her hat on indoors or during the playing of The National Anthem, unless it is considered unisex like a baseball cap. When wearing such a unisex cap, a woman should follow the same guidelines as for men.
Why are there different rules for men and women? It may have to do with the difference in the styles of men’s and women's hats.
Men's hats are easily removed, but women's hats with ribbons, bows, flowers and other decorations can be quite a production to remove, especially if they're anchored with hatpins. Women might also risk messing up their hairdos if they had to remove their hats. A lady, however, never wore brimmed hats after 5 PM, a fashion rule that developed because she didn't need a brim after sunset.