Why supra-conductivity became super-conductivity?

The original article by the Kamerlingh Onnes team in Leiden does not give a name to the new effect:

Kamerlingh Onnes, H. Further experiments with liquid helium. C. On the change of electric resistance of pure metals at very low temperatures, etc. V. The disappearance of the resistance of mercury. KNAW / Comm. Phys. Lab. Univ. Leiden 14 I, 115–122, Comm. 122b (1911).

(note I'm not even sure the title is the orginal one, I'm not sure the paper was in english, since KNAW refers to. I never put a hand on it...)

Few years latter, the name supra-conductivity was coined:

Kamerlingh Onnes, H. Further experiments with liquid helium. IX. The appearance of galvanic resistance in supraconductor, which are brought into a magnetic field at a threshold value of the field. KNAW / Comm. Phys. Lab. Univ. Leiden 16 II, 987–992, Comm. 139f (1914).

And the name stayed for a while, for instance in german articles:

Meissner, W. & Ochsenfeld, R. Ein neuer Effekt bei Eintritt der Supraleitfähigkeit. Naturwissenschaften 21, 787 (1933).

London, F. & London, H. Supraleitung und Diamagnetismus. Physica 2, 341 (1935).

or when it was about discussing this in english

London, F. & London, H. The electromagnetic equations of the supraconductor. Proc. Roy. Soc. Lond. A 149, 71–88 (1935).

Schrödinger, E. Phenomenological Theory of Supra-conductivity. Nature 137, 824–824 (1936).

But it has been changed to super-conductivity at some point, for instance in the London book

London, F. Superfluids, volume I: Macroscopic theory of superconductivity. (Dover Publications, Inc., 1961).

I wonder why...

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note that it's still called Supraleitung in German (and supraconductivité in French) – Christoph Oct 27 '13 at 9:59
...which you apparently already know – Christoph Oct 27 '13 at 10:17
This beautifully written soft-question appears to be off-topic because it seems to be about linguistics rather than actual physics. – Qmechanic Oct 27 '13 at 10:27
@Qmechanic Yes, I believe you're right. Maybe there is something more conceptual than the simple linguistics issue. In English, both super- and supra- prefixes exist. When I wrote it, I thought it was similar to this other question: physics.stackexchange.com/q/71759/16689 Nevertheless, feel free to move it to a more relevant place. Perhaps English-Language-and-Usage SE would be better: english.stackexchange.com – FraSchelle Oct 27 '13 at 15:51
@Christoph Even if I already knew, thanks for pointing this out :-) – FraSchelle Oct 27 '13 at 15:53