Science language indeed sounds so weird…

In English

Mathematics

• theory & theorem

  The difference between ‘theory’ and ‘theorem’.

  A theory is a rational type of abstract thinking about a phenomenon, or the results of such thinking. —Wikipedia

  In mathematics, a theorem is a statement that has been proved, or can be proved. —Wikipedia

  Taste: Information theory and asymptotic equipartition theorem.

From Latin

General Writing

• i.e. source

  Abbreviation for “id est”, a Latin phrase for “that is”, used especially in writing before a piece of information that makes the meaning of something clearer or shows its true meaning.

  • The hotel is closed during low season, i.e. from October to March.

  • The price must be more realistic, i.e. lower.

• e.g. source

  Abbreviation for “exempli gratia”: a Latin phrase that means “for example”.

  • You should eat more food that contains a lot of fibre, e.g. fruit, vegetables, and bread.

Mathematics

• QED source

  abbreviation for the Latin phrase “quod erat demonstrandum”: written or said after an argument to show that you have proved something that you wanted to prove.

• ad hoc source, source

  a Latin phrase meaning literally ‘for this’: made or happening only for a particular purpose or need, not planned before it happens:

  • on an ad hoc basis. We deal with problems on an ad hoc basis (= as they happen).
  • an ad hoc committee/meeting

Life Science

• in vivo source

  A Latin for “within the living”. It refers to work that’s performed in a whole, living organism.

• in vitro source

  A Latin for “within the glass”. When something is performed in vitro, it happens outside of a living organism.

• in situ source

  A Latin phrase that translates literally to “on site” or “in position.

• D- and L-configurations

  D: dextro, means right; L: leevo, means left

  In chemistry, the Fischer projection, devised by Emil Fischer in 1891, is a two-dimensional representation of a three-dimensional organic molecule by projection. Fischer projections were originally proposed for the depiction of carbohydrates and used by chemists, particularly in organic chemistry and biochemistry. source

  • D-Glucose, L-Alanine.

Other

• tuum est

  It is yours. / It is up to you. The motto of the University of British Columbia.

From Greek

Physics

• entropy from ἑντροπία

  In 1865, German physicist Rudolf Clausius, one of the leading founders of the field of thermodynamics, defined it as the quotient of an infinitesimal amount of heat to the instantaneous temperature. He initially described it as transformation-content, in German Verwandlungsinhalt, and later coined the term entropy from a Greek word for transformation. – Wikipedia

  Often called Shannon entropy, it was originally devised by Claude Shannon in 1948 to study the size of information of a transmitted message. – Wikipedia

• photon from φῶς

  Light.

Life Science

• haploid from ἁπλούς

  Single.

• diploid from διπλούς

  Double.

• metabolism from μεταωάλλειν

  To change or exchange.

Chemistry

• isomeric

  ἴσος (equal) + μέρος (part)

From German

Mathematics

• Eigen for eigenvalue, eigenfunction, eigenmode…

  own.

• Ansatz source

  An educated guess or an additional assumption made to help solve a problem, and which may later be verified to be part of the solution by its results.

  Example: see No.4 method to solve linear ODEs.

• Statistik source

  Description of a state, a country.

• $\mathbb Z$ for integers, Zählen

  To count.

Physics

• $Z$ for the partition function, Zustandssumme

  The sum over states.

• Bremsstrahlung source

  In particle physics, bremsstrahlung (from German bremsen ‘to brake’ and Strahlung ‘radiation’) is electromagnetic radiation produced by the deceleration of a charged particle when deflected by another charged particle, typically an electron by an atomic nucleus.

  If quantum effects are negligible, an accelerating charged particle radiates power as described by the Larmor formula and its relativistic generalization.

  此原理被用来制作 X 射线源：将电子加速到 10keV 左右然后达到金属靶上，则电子的减速（stopping）会产生连续谱的 X 射线（单色特征谱由靶原子中的电子向内层空穴月前所产生，是完全不同的另一种机制）。该现象最早又特斯拉（Nikola Tesla）于 1888-1897 年间研究高频电磁波现象时所发现。 韧致辐射的波谱依赖于带电粒子的能量和所遭遇的加速度。注意到对带电粒子的防护不可避免地设计对带电粒子的减速过程，因此要选用合适的低密度材料尽可能使得韧致辐射被转换为长波长的辐射以减少辐射带来的危害。这一点在航天科技中特别重要。——《物理学咬文嚼字（卷一）》曹则贤

• s-like, senkrecht

  s and p polarization. The electric field component parallel to the plane of incidence is termed s-like, from senkrecht, German for perpendicular.

From French

Physics

• propre

  The time $τ$ your watch registers (or, more generally, the time associated with the moving object) is called proper time. (The word suggests a mistranslation of the French “propre,” meaning “own.”) In some cases, $τ$ may be a more relevant or useful quantity than $t$. For one thing, proper time is invariant, whereas “ordinary” time depends on the particular reference frame you have in mind. – Griffiths’ Electrodynamics, 12.2.1 Proper Time and Proper Velocity