Thanks for sharing this info. Does "eccentricity" refer to the orbit, or the shape of the object?

For ‘Oumuamua in 2017, some method was used to determine its shape, which is (apparently) remarkably elongated. Is it possible to determine the elongation of the new object?

https://science.nasa.gov/solar-system/comets/oumuamua/

Eccentricity refers to the shape of the orbit, derivable from the highest and lowest distances in the orbit of the orbiting body (there's actually a bunch of ways to calculate it that are mathematically equivalent). It's related to modeling orbits as conic sections. An eccentricity of 0 is a perfect circle, <1 is a normal elliptical orbit, >=1 is an escaping trajectory.

For example, Earth's orbit around the sun is ~0.0167, Pluto's is 0.248.

We don't have enough data of the object yet to say basically anything at all about its shape.

To add what others said, eccentricity is also a way to tell if the object is captured or not. 0 means perfectly circular orbit, >=1 means escape, >=2 means hyperbolic.