An actress can be known for her emotional intelligence, her physical wit, her sensuality or her humor. She can be known for her versatility or her playfulness, or for her ability to deliver a dramatic monologue in pouring rain and not look silly.
As a Polish Nazi refugee: perfect. As a neglected corporate wife: perfect. As a single mom on a Greek island, dancing and belting out ABBA tunes: perfect. For her perfect portrayal of Julia Child in this year's "Julie & Julia," Streep is an Oscar nominee for a record 16th time.
But what about the early years, before Meryl Streep was Meryl Streep?
Watch "Before They Were Famous," on a special edition of "20/20" Tuesday, March 2 at 10 p.m. ET
ABC News recently sat down with two figures from Streep's past -- her best friend in high school and her graduate school drama coach -- to talk about the star's teenage days and her early stage career.
So what was she like back then? Pretty much perfect, it turns out.
"She was very outgoing. She had a great personality. Extremely funny," said Susan Castrilli, a friend of Streep's from Bernards High School in Bernardsville, N.J. "She was -- you know, I think the Meryl that you see now is the Meryl that was 14 years old. I don't think she's really changed all that much."
Michael Posnick directed Streep at the Yale School of Drama.
"It was just clear that there was something massive, monumental, really Himalayan about her work," Posnick said, "and about her gifts. And they're marvelous gifts. ... It's totally magic. There's a part of it that can't be explained. It's just an ability to become a character that represents a huge part [of] humanity. She's terribly human, wonderfully human."
Castrilli met Streep one summer day on the way to the pool. The Streep family had just moved to town.
"I used to cut through the woods to go to the community pool, and there was this blonde sitting on the porch there," said Castrilli. "It was a screened-in porch, and as I'm passing she looked up from a book she was reading. She said, 'Hello.' I said, 'Hello.' And she wound up at the high school."
Streep's given name is Mary Louise -- but she already was known as Meryl.
"Her mother gave it to her, actually," said Castrilli. "Her mother gave her the name Meryl because it was Mary Louise -- Mary L. She was named after her grandmother."
At high school, Streep was everywhere, Castrilli said. In addition to acting, she sang in the choir and was class treasurer and homecoming queen.
"She had a great personality that everybody liked," said her friend. "I mean, you know, she was just somebody that you wanted to be around because every minute was something different. She didn't like to linger on things for too long. She always liked to explore and see different things."
Streep was a cheerleader when Castrilli was captain of the squad.
"She was beautiful," Castrilli said. "Everybody loved to sit there and watch her with her short skirt jumping around. It was great. She's very athletic, and you had to be athletic to be a cheerleader. ... And she was not only athletic, but she looked great doing it."
Streep had her share of high school boyfriends, Castrilli said -- including one who would go on to make a name of his own.