It's the year that the coin was minted.
If you look under the date you can tell where it was minted, too:
"D" = Denver Mint
"S" = San Francisco
No letter = Philadelphia
A penny wirh a small date on it
The "D" indicates the coin was minted in the Denver mint
...If you can read the date on the penny, it is not an unstamped penny.
The letter "D" found beneath the date of the penny indicates the coin was minted in Denver, Colorado.
Assuming you mean a U.S. Indian Head cent and not a British penny, 1902 is a common date for Indian Head Cents. In average circulated condition it's worth $1.00-$3.00.
the date of a penny is on the front
A penny wirh a small date on it
It means that it was made at the San Francisco mint.
The "D" indicates the coin was minted in the Denver mint
Abraham Lincoln's on the front of the coin, and he was born in 1809. The date was put on the back for his bicentennial anniversary.
You probably mean date. Series is used when identify paper money. The date is on the right side on the front.
If you mean a Lincoln cent date 2010 or 2011 it's the Union Shield. If not, post new question with a date.
...If you can read the date on the penny, it is not an unstamped penny.
Cents struck at the Philadelphia mint don't have a mint mark.
"D" under the date on a Lincoln penny denotes it was minted in Denver.What_does_the_D_mean_on_a_US_pennyWhat_does_the_D_mean_on_a_US_penny
Your answer depends on the date on the penny.
If you mean a US small cent (1856 to date) the diameter is 19.2mm and the thickness at the rim is 1.55mm.