Main vein, Central vein, Mid vein are all correct to a point. "Rachis" seems to be the scientifically preferred term, though.
"Midrib" also sees some usage in a few types of leaf.
It is called a vein.
The central vein can be called a midrib or mid-vein
The main vein of a leaf is called the midrib. It provides structure and support to the leaf and helps transport water and nutrients throughout the leaf.
main vein / leaf blade
the line that goes through the middle of a leaf is called a vein.
The middle of a leaf is taken up by a vein called the midrib. -Andrew D.
The scientific term for the vein of a leaf is Xylem and phloem.
It depends on what sort of leaf. In broad leaved flowering plants it is normally down the middle. Gingko biloba doesn't have a main vein but many radiating from the stem. The Narrow leaved flowering plants have a series of so called main veins. The conifers don't have leaves, they have needles.
The large veins on the penis are called the dorsal veins of the penis.
The scientific term for the vein of a leaf is Xylem and phloem.
The central vein seen in the blade of a leaf is called the midvein or midrib. The bundle sheath is a layer of cells surrounding the vascular bundles in certain types of plant leaves, like in C4 plants. It is involved in the transport of water and nutrients within the leaf.
lateral vein is hindi ko alam