There is a Spanish word I learned back in the ’80s: tocayo. I was in Cuernavaca, visiting my aunt and uncle in their mostly gringo Jewish enclave. They brought me to a gathering at the home of friends, a Mexican Jewish family. There I was introduced to a young man with beautiful eyes and told he was my tocayo. That is, his name was Irwin.

I knew the English word “namesake,” and in fact my best friend in junior high was a namesake — an Irwin with whom I shared the bond of being the only Irwin either of us had ever met.

But tocayo, a Nahuatl word, felt different, stronger — more intimate and fateful than “namesake.” Here in the hills of Morelos, I never expected another Irwin; so tocayo felt deeper, like long-lost kin, separated twins, the answer to a shared mystery.

Irwin.

I was named after my grandfather, Irwin Keller, who died three years before I was born. When my parents discussed naming options for me, my now-widowed Grandma Minnie would always chime in, “You know, Irwin’s a good name.”

The name connected me with earlier generations, but was a frequent object of ridicule.

When I started Hebrew school, I needed a Hebrew name. My mother unearthed my bris certificate, which revealed the Hebrew name Yitzchak — Hebrew for Isaac.

Grandpa Irwin had seemingly never had a Hebrew name. His 1902 confirmation certificate from Temple Emanuel in Chicago was silent on the subject. So I thought Yitzchak was an impulsive sound-alike choice by the rabbi.

Over time I came to appreciate that the rabbi’s decision was not random. There was a near 1:1 correspondence between Old Country Jewish names and their U.S. secular equivalents. Nearly every Yitzchak became Irving (if Russian) or Irwin (if German). “Yitzchak” for me was convention, not caprice.

Not long ago, I found out that Grandpa Irwin’s father, Herman, was the son of Isaak Keller. I gasped as I realized that my Grandpa Irwin was named after his grandfather, Isaak. “Irwin” was a thin, secular veneer over a deeper, underlying Yitzchak. We were now three waves of Yitzchak Kellers. These two ancestors were my tocayos, reaching toward me through time as I reached back.

The name connected me with earlier generations, but was a frequent object of ridicule.

Two years ago I visited the German town the Kellers were from, a place of origin I’d only discovered weeks earlier. A day after my arrival I stood at great-great grandfather Isaak Keller’s grave on a drizzly hilltop in Waibstadt. Yitzchak ben Yehudah it said on the front face of the monument, Isack Keller on the back.

Isack Keller’s father, Judah, was buried there, and his stone was legible despite having been from 190 years earlier. There, with a shock, I saw his patronymic for the first time: Yehudah ben k’vod harav Yitzchak — Judah son of Rabbi Yitzchak. Yet another leapfrogged Yitzchak, making me the fourth of these, hopscotching through the generations, each named after a grandfather we never met.

I know virtually nothing about these German Yitzchak ancestors. I’ve seen their village and that enlivens my imagination. But I don’t know if they were short or tall, warm or withholding. I might look nothing like them; I might be nothing like them. I could actually have very little of their DNA. But I know I carry their Y-chromosome, which comes straight down the male line. And I guess I share with them the identification with a biblical boy bound to a stone by his father, rescued by an angel.

One Yitzchak, though, was not rescued. My Grandpa Irwin was not the only one named after great great Grandfather Isaak. Another Isaak Keller was born in 1877 outside Darmstadt. I was recently poking around on Ancestry.com, which was throwing “hints” at me, fast like batting practice, when it pitched a reference to that Isaak Keller. This was a death record: 1942. Dachau.

I silently caught my breath. The Kellers had always seemed immune to the Holocaust. My Kellers had come to the United States in the 1870s. But now this. Not just any Keller, but a tocayo.

I imagined someone with my own name at Dachau, and felt ill.

I wondered about my own Grandpa Irwin. Did he know that his first cousin and namesake was murdered? If so, who brought the news to America? Did he tell my father, only 17 at the time? Or did they never learn about it at all?

How strange this new world, where snippets of a person’s life can flow so far beyond their timely or untimely end. How strange that I can end up the first to have a long enough view to see the landscape of Yitzchak Kellers — their journeys, lives, deaths. The ones whose Judaism was casual and genteel. And the ones whose Judaism was a death sentence.

I have a big picture that my father and grandfather did not have. I want to show them, to tell them! I want to see what light it might shed on their lives. But they are all gone.

All I can do is look at the light this shines on my life. On the forces and circumstances that have allowed me to live in this place and time, with its freedoms and its risks. I live this particular life, carrying a name that has been borne by all those versions of me — tocayos over time and distance. Doing so with belated pride and purpose.

As Grandma Minnie would’ve said, “You know — Irwin’s a good name.”