Genesis 41:23

and, behold, seven ears withered, thin,* blighted with the east wind, sprang up after them.

‘TZ’NUMOTH,’ THIN. Tz’numa is Aramaic for “a rock.” That is, they are like wood without sap and hard as rock. But Onkelos translated, natzan lakyan (their blossom is stricken), i.e., there is nothing in them but their withered blossom because they were empty of grain. Thus the language of Rashi.
But ears of corn when empty of grain have no blossoms! Pharaoh also did not see the ears of corn when they blossomed; he saw them full and good, and thin, and parched with the east wind. Likewise, Rashi’s interpretation deriving tz’numoth from tz’numa as signifying “rocky” is also not correct. Thin ears of corn are not as hard as rocks.
But the meaning of tz’numoth is “separated,” [fragmented] into many pieces. It is the Rabbinic word: “Bread hatz’numa in a bowl requires the blessing of hamotzi,” the word hatz’numa meaning “cut bread,” or more exactly, pieces of bread in a bowl upon which he pours soup, and each part is eaten without any other bread. This likewise is the meaning of the Targum, who uses the word natzan, which signifies “cut and deficient.”
The usage of the word natza is similar to that in the saying of the Rabbis: “If one transfers dirt from a malya into malya or natza into natza, it does not constitute taking possession, but if he takes malya and throws it into natza, it does constitute an act of taking possession.” Now a high place in a field solidly filled with earth is called malya, and one in which there is an appreciable shortage of earth is called natza. to another, or from one natza to another, he has not improved the land. Hence it does not constitute an act of taking possession. But if he took earth from a malya and filled in a natza, he has performed a constructive act, and it therefore constitutes an act of taking possession. Here likewise the opposite of “full ones” is tz’numoth, and (the singular) natzan is the opposite of malyan (a full one).
The situation described here in the verse is that the ears were not full of grain but that there were empty spots without grain in them, and in other places, higher up on the stalk, the ears were wind-beaten and empty. This was why Joseph used the word reikoth (empty ones), instead of tz’numoth as there were there places on the ears which contained no grain whatever.

וצנומות, its meaning is in accordance with the context in which the word appears. It is unique in Scriptures. One may suggest that the word means the same as in the Talmud Baba Batra 18 where it refers to something hard as stone, devoid of any moisture.

צנמות, a word which is understood based on our sages (Rashi, Ram’ban) quoting the expressionפת צנומה בקערה (Berachot 39, “dried bread placed in a dish to soak it in water.”) The interpretation of the dream is now perfectly clear.