"Undergraduate work" refers to the academic work or studies that students pursue at the college or university level, typically before they earn a bachelor's degree.
I've done drawing and some painting since undergraduate work at design school years ago. (eastcityart.com)
Three years of undergraduate work doesn't cut it any more. (slaw.ca)
My advice to young people wanting to get into planetary exploration or any space field is to make use of undergraduate work experience opportunities such as co-op programs and similar programs. (sciencemag.org)