Mi Webster's ha le sequente pro "thunder":

1.      thunder  n  [ME thoner, thunder, fr. OE thunor;
        akin to OHG thonar thunder, L tonare to thunder]

Il non es evidente a me si le latino L. tonare veni del germanic
o es solmente un cognate indoeuropee.  Listate sub le parola
"tone" (tono) in mi Webster's es:
1. tone  n  [ME, fr. L tonus tension, tone, fr. Gk tonos, lit.,
    act of stretching; akin to Gk teinein to stretch  more at THIN]
1  : vocal or musical sound of a specific quality <spoke in low s >
     <masculine s >; esp : musical sound with respect to timbre and
      manner of expression
2
a  : a sound of definite pitch and vibration
b  : WHOLE STEP
3  : accent or inflection expressive of a mood or emotion
4  : the pitch of a word often used to express differences of meaning
5  : a particular pitch or change of pitch constituting an element in the
     intonation of a phrase or sentence <high > <low > <mid >
     <low-rising > <falling >
6  : style or manner of expression in speaking or writing <seemed wise to
     adopt a conciliatory >
7
a
(1)  : color quality or value
(2)  : a tint or shade of color
b  : the color that appreciably modifies a hue or white or black
     <gray walls of greenish >
8  : the effect in painting of light and shade together with color
9
a  : the state of a living body or of any of its organs or parts in which
     the functions are healthy and performed with due vigor
b  : normal tension or responsiveness to stimuli; specif : muscular tonus
10
a  : healthy elasticity : RESILIENCY
b  : general character, quality, or trend <a city's upbeat >
c  : frame of mind : MOOD

2. tone  vb  toned; toning vt (1660)
1  : INTONE
2  : to give a particular intonation or inflection to
3
a  : to impart tone to : STRENGTHEN <medicine to  up the system>
b  : to soften or reduce in intensity, color, appearance, or sound : MELLOW
      often used with down
c  : to change the normal silver image of (as a photographic print) into
     a colored image  vi
1  : to assume a pleasing color quality or tint
2  : to blend or harmonize in color

Le tono es un sono.  On pensarea que il habeva un verbo "tonare" pro
"tonificar" :-).  Evidentemente le latino "tonare" non es de origine
grec o latin, mais germanic?

Stan Mulaik