A tanur (an oven shaped like a conical pot, this was made of earthenware covered in clay and lacked a bottom, and rested on the ground),

its beginning [for it to be considered a vessel susceptible to tumah] is with [a height of]  four [handbreadths],

and its remnants four (if broken, the remnants must be four handbreadths high to retain the ability to become tamei),

these are the words of Rabbi Meir;

and the Sages say,

by what are we speaking,

by a large [tanur]

but with a small [tanur]

its beginning is the smalled amount

and its remnants are its majority;

[the above rule applies] from when its manufacture is complete.

What is the completion of its manufacture?

From when one heats it

enough to bake in it sponge cakes (which had a thin, watery batter, and required a relatively low heat);

Rabbi Yehuda says

when you heat a new [tanur] (which did not retain heat as well)

sufficiently to bake in an old [tanur] (which retained more heat, and so required less of it)

sponge cakes.

פרק ה משנה ב

A kirah (a cylindrical oven, this was also made of earthenware and lacked a bottom, rested on the ground, and could hold two pots at a time, some say inside it, some say on top of it as well; this vessel did not get as hot as a tanur),

its beginning is with three [finger-breadths]

and its remnants are are three [finger-breadths],

from when its manufacture is complete.

What is the completion of its manufacture?

From when one heats it

to cook on it

the most easily cooked egg to cook

[which has been] beaten and put in a [preheated] stewpot.

A kupach (this was a cylindrical earthenware cooking vessel which could be used as a stove or an oven, could hold one pot, and got hotter than a kirah),

if made for baking,

its measure is as of a tanur,

if made for cooking,

its measure is as of a kirah.

The stone (this was embedded into the outside of a cooking vessel to serve as a handle; some say this was the coating on the outside of the earthenware vessel made of stones and clay, to protect and insulate it)

that extended from a tanur

a handbreadth

and from a kirah

three finger-breadths

is a connected (such that it has the status of a yad and will contract tumah when the rest of the vessel does and will impart tumah to food);

that which extends from a kupach,

if made for baking,

its measure is as of a tanur,

if made for cooking,

its measure is as of a kirah;

Rabbi Yehuda says

they did not say [the measure of] a handbreadth

but for that which is between the tanur and the wall (of the house; when it did not extend into the space between the tanur and the wall of the house, then it could be even longer and retain the status of a yad).

If there were two tanurin

next to each other

to this one is given a handbreadth

and to this one a handbreadth,

and the rest (that which is not within a handbreadth of either tanur) is tahor.