How about Disproportionation? (When a single species is simultaneously oxidised and reduced)

Pneumonoultramicroscopicsilicovolcanoconiosis

Longest word in dictionary. "a factitious word alleged to mean 'a lung disease caused by the inhalation of very fine silica dust, causing inflammation in the lungs"

I remembered it from somewhere, googled longest word, and here i am

Floccinaucinihilipipification.


The habit of estimating someone or something as worthless.

Deoxyribonucleic Acid
DNA unabreviated

Sense.

Your thread title makes none of it.

Pneumono-: a combining form meaning "lung"
-ultramicroscopic-: an instrument that uses scattering phenomena to detect the position of objects too small to be seen by an ordinary microscope.
-silico-: the dioxide form of silicon, SiO 2 , occurring especially as quartz sand, flint, and agate: used usually in the form of its prepared white powder chiefly in the manufacture of glass, water glass, ceramics, and abrasives.
-volcano-: a vent in the earth's crust through which lava, steam, ashes, etc., are expelled, either continuously or at irregular intervals.
(pneumono)-coniosis: any chronic lung disease, including anthracosis, asbestosis, and silicosis, caused by the inhalation of particles of coal, asbestos, silica, or similar substances and leading to fibrosis and loss of lung function.

What about the full chemical name for Titin? (Although it's debatable whether it is actually a word, seeing as the name is effectively a list of amino acids in the protein. The chemical formula is C132983H211861N36149O40883S693)

D: i was gonna say that

electroencephalographically

definition: cant remember

Methionylglutaminylarginyltyrosylglutamyl...serine is a weird science substance