Peel (rind)The tough outer covering. It has two layers, the thin zest outside and the spongy pith under it.
Oil glandsSmall pockets in the peel that hold the lemon's fragrant oil. They show as fine dots all over the fruit.
Button (calyx)The small leafy cap at the stem end. Pickers leave it on, because pulling it off opens a way in for rot.
Tip (nipple)The bump at the end opposite the stem. Growers call it the nipple, and its size helps tell one lemon variety from another.
Cut across 7
Zest (flavedo)The thin outer layer of the peel. The oil glands sit in it, which is why grated zest smells so strongly of lemon.
Pith (albedo)The spongy inner layer of the peel. It lies between the zest and the segments. In a real lemon it is white.
SegmentOne wedge of the fruit. A lemon has about 8 to 10, and each is a separate chamber full of juice sacs.
Segment membraneThe thin wall that separates one segment from the next. Old fruit books call these walls partitions or septa.
Juice sacs (juice vesicles)Small bags packed side by side inside every segment. They hold the juice, and together they are the pulp.
SeedSeeds grow inside the segments. Most lemons have a few, and some have none.
Core (central axis)The column down the middle of the fruit. It runs from the stem end to the tip. The segments are gathered round it.
How this list was compiled: Every name checked on 2026-09-30 against sources read that day; a name is kept only where two of them use it: (1) Julia F. Morton, Lemon, in Fruits of Warm Climates (1987), Purdue University NewCROP, https://hort.purdue.edu/newcrop/morton/lemon.html; (2) J. Eliot Coit, Citrus Fruits (1915, public domain), https://archive.org/details/citrusfruits00coit, with H. Harold Hume, Citrus Fruits and Their Culture (1913, public domain), https://archive.org/details/citrusfruitsthei00humerich; (3) two University of Florida dissertations on citrus fruit, C. A. Lowell (1986), https://archive.org/details/structuresucrose00lowe, and M. W. Fidelibus (2002), https://archive.org/details/horticulturalmec00fide, counted as one source; (4) Wikipedia, Lemon, Citrus, Hesperidium, Zest (ingredient) and Juice vesicles (text only). Hints and detail lines are in our own words. Licence: own work
The drawing: Drawn for this site on 2026-09-30 from plain geometry; nothing traced or copied. Licence: own work
How it works
The first drawing shows the parts of a lemon fruit from outside, with a patch of peel enlarged to show its oil glands. The second is the lemon cut across, with the juice sacs of one segment enlarged.
Read the full guide
Outside first, then the cut lemon
Numbers 1 to 4 are on the whole lemon: the peel, the oil glands that dot it, the button where the stem was, and the tip at the other end. Numbers 5 and 6 are the two layers of the peel, the zest and the pith. Numbers 7 to 9 are a segment, the membrane between two segments and the juice sacs that fill each one. Numbers 10 and 11 are a seed and the core.
Zest and pith together are the peel. Zest is the thin outer layer a grater takes off; pith is the spongy layer under it.
The pulp is not one solid mass. It is made of separate juice sacs, each a tiny bag of juice.
Questions and answers
What are the parts of a lemon?
From outside in: the peel, made of the zest and the pith under it; the segments, each wrapped in a thin membrane and filled with juice sacs; the seeds; and the core down the middle. The button marks the stem end.
What is the white part of a lemon called?
The pith, or albedo. It is the spongy inner layer of the peel, between the zest and the segments.
What kind of fruit is a lemon?
A hesperidium, which is a berry with a leathery rind. Oranges and the other citrus fruits are built the same way, with a rind round juicy segments.
How many segments does a lemon have?
Usually 8 to 10. Each segment is one chamber of the fruit, and its seeds, if it has any, grow inside it.