The name "Iyar" is, like the others in the Hebrew Calendar, of Babylonian origin. The Torah itself refers to the month as the "Second Month," with relation to Nisan, the First of the Months.
It is also referred to in the Bible (Melachim Aleph, Ch. 6) as "Chodesh Ziv," meaning the Month of Splendor." This is because of the splendor of the sun during this month, when it has reached the height of its brilliance, but does not yet burn with the (sometimes harmful) intensity that it does in the late summer months.
Another reason for the use of this name is that the "Targum," Translation from the Aramaic, of the word "Ziv," is "Nitzan," meaning blossom. And this is the time of year when lovely flower blossoms appear in Eretz Yisrael, as it says in "Shir HaShirim," the Song of Songs, by Shlomo HaMelech, "HaNitzanim niru ba'aretz, et hazamir higia;" "Blossoms have appeared in the Land; the time for song has arrived." (Shir HaShirim, 2:12)
Yet another reason is that all the Jews who left Egypt, many of whom had known nothing but slavery for some two hundred years, had numerous physical blemishes and injuries to show for the "pleasure" of that experience, an eye missing here, an ear there, broken limbs all over. Yet they were all returned miraculously "to their splendor," by the Healer of the World, prior to their meeting at Sinai with G-d to receive the Torah.
The "Mazal," the Zodiac Sign
The Sign of the Month is an ox eating grass, corresponding to the fact that this is the last month in the warm season in Eretz Yisrael that the ox can find enough grass to satisfy its appetite from the grass of the field.
"Pesach Sheni," Second Pesach
The fourteenth of Iyar is known as the "Second Pesach" because it was on that date that Jews had a "second chance" at participating in the rituals of Pesach, if they'd been unable to do so in Nisan, because of ritual uncleanness or because they had been far away from home at that time. In particular, they were given the opportunity to bring a Pesach sacrifice and eat it with Matzah and Marror a month after the original Holiday.
This is a very unique Holiday, because it is rare that we find an instance of a "second chance" being granted to perform a commandment. In general, the rule followed is "avar zemano, batel korbano;" literally, "if the proper time for the sacrifice has passed, it can no longer be brought." More generally, if one is presented with an opportunity to achieve something good in the world, he or she should be sure to take advantage of it before it becomes "too late" one way or another.
Why is Pesach different from all the other holidays?
Perhaps it is because of the importance of Pesach in the life of the Jew. Pesach is that time of year in which a Jew most closely identifies with his People. He "bonds," to use a terribly over-used word, with the Jewish People over space and time, reliving its tragedies and its triumphs. It is "designed" to be a truly "once-in-a-lifetime," or at least, once-in-a-year, experience!
But, if because of circumstances he could not control, he was not able to participate the first time around, in Nisan, the Torah allows him a "second chance," in Iyar.
Iyar is a month of tragedy and triumph, encompassing "Yom HaZikaron," commemorating those who gave their lives for Eretz Yisrael, and "Yom Yerushalayim," the day marking the return of the Jewish People, with the help of G-d, to their capital city and the Temple Mount.
Let us not fail to take advantage of this "Second Chance" that we have been given to build a Jewish State and Jewish lives that will reflect G-dly principles, in their full "Ziv," or Splendor.