Question: Which Latin word does quantum come from?
About the article "Quantum", section "Etymology and discovery".

Candidate passages:
The word "chancre" () means "little ulcer" in Old French.
Related to the English "canker", they both come from the Latin "cancer", meaning "crab", which is a translation from the Greek word "καρκἰνος (karkínos)", also meaning "crab". 
"Oiko" is derived from the Greek word "oikos", which means "the house, the place where the people live together".
The word "credit" does not only refer to financial credit, but also to the Latin verb, "credere", "to believe". 
Main subjects of research.
Quantum-like models of information processing ("quantum-like brain").
The brain is definitely a macroscopic physical system operating on the scales (of time, space, temperature) which differ crucially from the corresponding quantum scales.
(The macroscopic quantum physical phenomena such as e.g.
the Bose-Einstein condensate are also characterized by the special conditions which are definitely not fulfilled in the brain.)
In particular, the brain is simply too hot to be able perform the real quantum information processing, i.e., to use the quantum carriers of information such as photons, ions, electrons.
As is commonly accepted in brain science, the basic unit of information processing is a neuron.
It is clear that a neuron cannot be in the superposition of two states: firing and non-firing.
Hence, it cannot produce superposition playing the basic role in the quantum information processing.
Superpositions of mental states are created by complex neural networks of neurons (and these are classical neural networks).
Quantum cognition community states that the activity of such neural networks can produce effects which are formally described as interference (of probabilities) and entanglement.
In principle, the community does not try to create the concrete models of quantum (-like) representation of information in the brain.
The quantum cognition project is based on the observation that various cognitive phenomena are more adequately described by quantum information theory and quantum probability than by the corresponding classical theories, see examples below.
Thus the quantum formalism is considered as an operational formalism describing nonclassical processing of probabilistic data.
Recent derivations of the complete quantum formalism from simple operational principles for representation of information supports the foundations of quantum cognition.
The subjective probability viewpoint on quantum probability which was developed by C. Fuchs and collaborators also supports the quantum cognition approach, especially using of quantum probabilities to describe the process of decision making.
Although at the moment we cannot present the concrete neurophysiological mechanisms of creation of the quantum-like representation of information in the brain, we can present general informational considerations supporting the idea that information processing in the brain matches with quantum information and probability.
Here, contextuality is the key word, see the monograph of Khrennikov for detailed representation of this viewpoint.
Quantum mechanics is fundamentally contextual.
Quantum systems do not have objective properties which can be defined independently of measurement context.
(As was pointed by N. Bohr, the whole experimental arrangement must be taken into account.)
Contextuality implies existence of incompatible mental variables, violation of the classical law of total probability and (constructive and destructive) interference effects.
Thus the quantum cognition approach can be considered as an attempt to formalize contextuality of mental processes by using the mathematical apparatus of quantum mechanics. 
In quantum information theory, quantum discord is a measure of nonclassical correlations between two subsystems of a quantum system.
It includes correlations that are due to quantum physical effects but do not necessarily involve quantum entanglement.
The notion of quantum discord was introduced by Harold Ollivier and Wojciech H. Zurek and, independently by L. Henderson and Vlatko Vedral.
From the work of these two research groups it follows that quantum correlations can be present in certain mixed separable states; In other words, separability alone does not imply the absence of quantum effects.
The notion of quantum discord thus goes beyond the distinction which had been made earlier between entangled versus separable (non-entangled) quantum states. 
The word "plăcintă" comes from Latin "placenta" which means "cake".