
Thinking that the best way to understand something might be to actually look at what's being described, I've posted a picture here of four Tarjetas Postales.
The
card at the lower right
is a 2 centavos red oval.
The reverse of the card - not reproduced here - has a written date
of October 25, 1892, and what appears to be a rubber-stamped
advertisement from Irapuato. We mention this, because
it is always a good idea to check the back of the card for
information (like a date) that can be helpful in identifying an
item.
The
postal card in the upper left-hand corner is
a 2 cent Mulita issue in red,
uncirculated.
The last two cards - one in the upper right corner, one in the lower left - are both 3 centavos, brown, mulitas issues. One card is for international sending, the other one is for Servicio Interior (domestic service). You can see the "Servicio Interior" designation on the card at the top right on both sides of the card. Conversely, the international card on the bottom left has a Universal Postal Union designation (in Spanish on the left side, and in French on the right side). Both are uncirculated.
Postal cards (tarjetas postales, in Spanish) are postcards issued by the government post office, with postage already imprinted on the card.